criyle/codenet-compile-errors huggingface dataset:
Language: C++

#include <bits/stdc++.h>
using namespace std;
 
int main()
{
  long a, b, c, d, x, y;
  long ac, bd;
  cin >> a >> b >> c >> d;
  
  if(b > 0 && d > 0){
    if(a < 0 && c < 0){
      ac = a * c;
      bd = b * d;
      if(ac >= bd){
        x = a; y = c;
      }
    }else{
  	x = b;
    y = d;}
  }if(b < 0 && d > 0){
    if(a < 0 && c < 0){
      ac = a * c;
      bd = b * d;
      if(ac >= bd){
        x = a; y = c;
    }else{
    x = b;
    y = c;}
  }if(b > 0 && d < 0){
    if(a < 0 && c < 0){
      ac = a * c;
      bd = b * d;
      if(ac >= bd){
        x = a; y = c;
      }
    }else{
    x = a;
    y = d;}
  }if(b < 0 && d < 0){
    x = a;
    y = c;
  }if(b == 0 && c < 0){
    x = a;
    y = c;
  }if(a < 0 && d == 0){
    x = a;
    y = c;
  }if(b == 0 && d == 0){
    x = a;
    y = c;
  }
  
  cout << x * y << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:54:2: error: expected '}' at end of input
   54 | }
      |  ^
a.cc:5:1: note: to match this '{'
    5 | {
      | ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
 
int main()
{
  long a, b, c, d, x, y;
  long ac, bd;
  cin >> a >> b >> c >> d;
  
  if(b > 0 && d > 0){
    if(a < 0 && c < 0){
      ac = a * c;
      bd = b * d;
      if(ac >= bc){
        x = a; y = c;
      }
    }else{
  	x = b;
    y = d;}
  }if(b < 0 && d > 0){
    if(a < 0 && c < 0){
      ac = a * c;
      bd = b * d;
      if(ac >= bc){
        x = a; y = c;
    }else{
    x = b;
    y = c;}
  }if(b > 0 && d < 0){
    if(a < 0 && c < 0){
      ac = a * c;
      bd = b * d;
      if(ac >= bc){
        x = a; y = c;
      }
    }else{
    x = a;
    y = d;}
  }if(b < 0 && d < 0){
    x = a;
    y = c;
  }if(b == 0 && c < 0){
    x = a;
    y = c;
  }if(a < 0 && d == 0){
    x = a;
    y = c;
  }if(b == 0 && d == 0){
    x = a;
    y = c;
  }
  
  cout << x * y << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:14:16: error: 'bc' was not declared in this scope; did you mean 'bd'?
   14 |       if(ac >= bc){
      |                ^~
      |                bd
a.cc:24:16: error: 'bc' was not declared in this scope; did you mean 'bd'?
   24 |       if(ac >= bc){
      |                ^~
      |                bd
a.cc:33:16: error: 'bc' was not declared in this scope; did you mean 'bd'?
   33 |       if(ac >= bc){
      |                ^~
      |                bd
a.cc:54:2: error: expected '}' at end of input
   54 | }
      |  ^
a.cc:5:1: note: to match this '{'
    5 | {
      | ^
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  int a,b,c,d;
  cin >> a >> b >> c >> d;
  int p,q;
  if (b % 2 = 1){
    p = 1;
  }
  else {
    p = -1;
  }
  if (c % 2 = -1){
    q = -1;
  }
  else {
    q = 1;
  }
  if (p == 1 && q == 1){
    cout << b * d;
  }
  else if (p > q)
    cout << a * c;
  }
  else if (p < q)
    cout << a * c;
  }
  else if (p == -1 && q == -1)
    cout << b * d;
  }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:9: error: lvalue required as left operand of assignment
    8 |   if (b % 2 = 1){
      |       ~~^~~
a.cc:14:9: error: lvalue required as left operand of assignment
   14 |   if (c % 2 = -1){
      |       ~~^~~
a.cc: At global scope:
a.cc:26:3: error: expected unqualified-id before 'else'
   26 |   else if (p < q)
      |   ^~~~
a.cc:28:3: error: expected declaration before '}' token
   28 |   }
      |   ^
a.cc:29:3: error: expected unqualified-id before 'else'
   29 |   else if (p == -1 && q == -1)
      |   ^~~~
a.cc:31:3: error: expected declaration before '}' token
   31 |   }
      |   ^
a.cc:32:1: error: expected declaration before '}' token
   32 | }
      | ^
Language: C++

#include<bits/stdc++.h>
#include <cassert>
#include <algorithm>
#include <functional>
using namespace std;
int main() {
  	//a≤x≤b,c≤y≤d を満たす整数 x,y について、x×y の最大値はいくつですか。
	int a;
  	int b;
	int c;
	int d;
	cin >> a >> b >> c >> d;
	
  	int ilc = 0;
  	int arr = {a*c, a*d, b*c, b*d} ;
  	int ans = arr[0];
	while(ilc != 4){
      int next = arr[ilc + 1];
      if (ans < next){
        ans = next;
      } else {
        //no deal
      }      
      ++ilc;
    }
  	cout << ans << "\n";
}

Compiler output:
a.cc: In function 'int main()':
a.cc:15:13: error: scalar object 'arr' requires one element in initializer
   15 |         int arr = {a*c, a*d, b*c, b*d} ;
      |             ^~~
Language: C++

#include <fstream>
#include <iostream>
#include <algorithm>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string>
#include <sstream>
#include <map>
#include <set>
#include <vector>
#include <stack>
#include <cmath>
#include <queue>
#include <random>

using namespace std;
struct XX{
int s;
    int e;
};

class xxGreater {
public:
bool operator()(const XX& riLeft, const XX& riRight) const {
        //第2条件
if((riLeft.s) == (riRight.s)){
return riLeft.e < riRight.e;//<:昇順(小さいものから順番)、>:降順(大きいものから順番)
           //プライオリティキューの場合は > で、top()すると値の小さいものがとれる
        }
        //第1条件
        return (riLeft.s) > (riRight.s);
    }
};


int main(int argc, const char * argv[])
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    
    int a,b,c,d;
    cin >> a>> b>>c>>d;
int ans==0;
ans=max(ans,a*c);
ans=max(ans,a*d);
ans=max(ans,b*c);
ans=max(ans,b*d);


cout << ans <<endl;

}


//cout << "Hello World" << endl;

Compiler output:
a.cc: In function 'int main(int, const char**)':
a.cc:44:8: error: expected initializer before '==' token
   44 | int ans==0;
      |        ^~
a.cc:45:1: error: 'ans' was not declared in this scope; did you mean 'abs'?
   45 | ans=max(ans,a*c);
      | ^~~
      | abs
Language: C++

#include<iostream>
#include<boost/multiprecision/cpp_int.hpp>
#include<algorithm>
using namespace std;
using boost::multiprecision;
int main()
{
  ios::sync_with_stdio(false);
  int256_t a, b, c, d;
  cin>>a>>b>>c>>d;
  int1024_t x, y;
  x = max(a*c, a*d);
  y =max(b*c, b*d);
  cout<<max(x, y);
  return 0;
}

Compiler output:
a.cc:2:9: fatal error: boost/multiprecision/cpp_int.hpp: No such file or directory
    2 | #include<boost/multiprecision/cpp_int.hpp>
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
Language: C++

#include <bits/stdc++.h>
using namespace std;
#define LL long long

int main() {
  LL A,B,C,D;
  cin>>A>>B>>C>>D;
   if(D<0&&A>0){
   cout<<A*D<<endl;
 }
 else if(B<0&&C>0){
   cout<<B*C<<endl;
 }
 else if(A*C<B*D){
  cout<<B*D<<endl;
  }
  else if(A*C>B*D){
    cout<<A*C<<endl;
  }
  else if(A*C==B*D){
    cout<<A:c<<endl;
  }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:21:12: error: found ':' in nested-name-specifier, expected '::'
   21 |     cout<<A:c<<endl;
      |            ^
      |            ::
a.cc:21:11: error: 'A' is not a class, namespace, or enumeration
   21 |     cout<<A:c<<endl;
      |           ^
Language: C++

 #include <iostream>
#include <stdlib.h>
using namespace std;

int main(){
  	long long a,b,c,d;
  	cin >> a >> b >> c >> d;
  	cout << max([a*c,a*d,b*c,b*d]) << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:8:23: error: expected ',' before '*' token
    8 |         cout << max([a*c,a*d,b*c,b*d]) << endl;
      |                       ^
      |                       ,
a.cc:8:23: error: expected identifier before '*' token
a.cc:8:25: error: expected ']' before ',' token
    8 |         cout << max([a*c,a*d,b*c,b*d]) << endl;
      |                         ^
      |                         ]
a.cc: In lambda function:
a.cc:8:25: error: expected '{' before ',' token
a.cc: In function 'int main()':
a.cc:8:37: error: expected ')' before ']' token
    8 |         cout << max([a*c,a*d,b*c,b*d]) << endl;
      |                    ~                ^
      |                                     )
Language: C++

#include<iostream>
using namespace std;
int main()
{
  int a,b,c,d;
  cin >> a >> b >> c >> d;
  
  array[3]= {a*d,b*c,b*d};
  int out = a*c;
  for(auto a : array){
    if(a > out){
    	out = a;
    }
  }
  
  cout << out;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:9: error: expected identifier before numeric constant
    8 |   array[3]= {a*d,b*c,b*d};
      |         ^
a.cc:8:9: error: expected ']' before numeric constant
    8 |   array[3]= {a*d,b*c,b*d};
      |         ^
      |         ]
a.cc:8:8: error: empty structured binding declaration
    8 |   array[3]= {a*d,b*c,b*d};
      |        ^
a.cc:10:21: error: missing template arguments before ')' token
   10 |   for(auto a : array){
      |                     ^
Language: C++

 #include <iostream>
#include <stdlib.h>
using namespace std;

int main(){
  	long long a,b,c,d;
  	cin >> a >> b >> c >> d;
  	cout << max(a*c,a*d,b*c,b*d) << endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:8:20: error: no matching function for call to 'max(long long int, long long int, long long int, long long int)'
    8 |         cout << max(a*c,a*d,b*c,b*d) << endl;
      |                 ~~~^~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/string:51,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   candidate expects 2 arguments, 4 provided
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 4 provided
Language: C++

#include<iostream>
using namespace std;
int main()
{
  int a,b,c,d;
  cin >> a >> b >> c >> d;
  
  array[]= {a*d,b*c,b*d};
  int out = a*c;
  for(auto a : array){
    if(a > out){
    	out = a;
    }
  }
  
  cout << out;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:8: error: empty structured binding declaration
    8 |   array[]= {a*d,b*c,b*d};
      |        ^~
a.cc:10:21: error: missing template arguments before ')' token
   10 |   for(auto a : array){
      |                     ^
Language: C++

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;



int main(){
    int a, b, c, d;
    vector<long long int> ans;

    cin >> a >> b >> c >> d;
/*
    long long int x = (long long int)a * (long long int)c;

    cout << a << endl;
    cout << x << endl;

    return 0;
*/
    
    long long int x, max;
    max = LONG_MIN;
    x = (long long int)a * (long long int)c;
    if( x > max ){
        max = x;
    }
    ans.push_back(x);

    x = (long long int)a * (long long int)d;
    if( x > max ){
        max = x;
    }    
    ans.push_back(x);

    x = (long long int)b * (long long int)c;
    if( x > max ){
        max = x;
    }
    ans.push_back(x);

    x = (long long int)b * (long long int)d;
    if( x > max ){
        max = x;
    }
    ans.push_back(x);


    //sort(ans.begin(), ans.end(), greater<int>());

    cout << max << endl;
    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:23:11: error: 'LONG_MIN' was not declared in this scope
   23 |     max = LONG_MIN;
      |           ^~~~~~~~
a.cc:4:1: note: 'LONG_MIN' is defined in header '<climits>'; this is probably fixable by adding '#include <climits>'
    3 | #include <algorithm>
  +++ |+#include <climits>
    4 | using namespace std;
Language: Java

import java.util.*;
public class MyClass {
    public static void main(String args[]) {
      Scanner sc = new Scanner(System.in);
      long A = sc.nextLong();
      long B = sc.nextLong();
      long C = sc.nextLong();
      long D = sc.nextLong();
      
      if(A >= 0 && B >= 0 && C >= 0 && D >= 0) {
          System.out.print(Math.max(A, B) * Math.max(C, D));
      }
      else if(A >= 0 && B >= 0 && C < 0 && D < 0) {
          System.out.print(Math.min(A, B) * Math.max(C, D));
      }
      else if(A < 0 && B < 0 && C >= 0 && D >= 0) {
          System.out.print(Math.max(A, B) * Math.min(C, D));
      }
      else if(((A < 0 && B > 0) || (A > 0 && B < 0)) && ((C < 0 && D > 0) || (C > 0 && D < 0))) {
          long val1 = Math.max(A, B) * Math.max(C, D);
          long val2 = Math.min(A, B) * Math.min(C, D);
          long val3 = Math.max(A, B) * Math.min(C, D);
          long val4 = Math.min(A, B) * Math.max(C, D);
          
          long max1 = Math.max(val1, val2);
          long max2 = Math.max(val3, val4);
          
          System.out.print(Math.max(max1, max2));
      }
    }
}

Compiler output:
Main.java:2: error: class MyClass is public, should be declared in a file named MyClass.java
public class MyClass {
       ^
1 error
Language: Java

import java.util.Scanner;
import java.util.*;

public class solution{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int d = sc.nextInt();
    int x = Math.max(a,b);
    int y = Math.max(c,d);
    System.out.println(x*y);
  }
}

Compiler output:
Main.java:4: error: class solution is public, should be declared in a file named solution.java
public class solution{
       ^
1 error
Language: C++

#include<cstdio>
#include<algorithm>
using namespace std;
int main(void)

	long long int a,b,c,d,x[4]={0},y,i;
	scanf("%lld %lld %lld %lld",&a,&b,&c,&d);
	x[0]=a*d;
	x[1]=a*c;
	x[2]=b*c;
	x[3]=b*d;
	y=x[0];
	for(i=0;i<4;i++){
		if(y<x[i]) y=x[i];
	}
	printf("%lld\n",y);
	return 0;
}


Compiler output:
a.cc:6:9: error: expected initializer before 'long'
    6 |         long long int a,b,c,d,x[4]={0},y,i;
      |         ^~~~
a.cc:6:39: error: expected unqualified-id before ',' token
    6 |         long long int a,b,c,d,x[4]={0},y,i;
      |                                       ^
a.cc:6:41: error: expected constructor, destructor, or type conversion before ',' token
    6 |         long long int a,b,c,d,x[4]={0},y,i;
      |                                         ^
a.cc:6:43: error: expected constructor, destructor, or type conversion before ';' token
    6 |         long long int a,b,c,d,x[4]={0},y,i;
      |                                           ^
a.cc:7:14: error: expected constructor, destructor, or type conversion before '(' token
    7 |         scanf("%lld %lld %lld %lld",&a,&b,&c,&d);
      |              ^
a.cc:8:9: error: 'x' does not name a type
    8 |         x[0]=a*d;
      |         ^
a.cc:9:9: error: 'x' does not name a type
    9 |         x[1]=a*c;
      |         ^
a.cc:10:9: error: 'x' does not name a type
   10 |         x[2]=b*c;
      |         ^
a.cc:11:9: error: 'x' does not name a type
   11 |         x[3]=b*d;
      |         ^
a.cc:12:9: error: 'y' does not name a type
   12 |         y=x[0];
      |         ^
a.cc:13:9: error: expected unqualified-id before 'for'
   13 |         for(i=0;i<4;i++){
      |         ^~~
a.cc:13:17: error: 'i' does not name a type
   13 |         for(i=0;i<4;i++){
      |                 ^
a.cc:13:21: error: 'i' does not name a type
   13 |         for(i=0;i<4;i++){
      |                     ^
a.cc:16:15: error: expected constructor, destructor, or type conversion before '(' token
   16 |         printf("%lld\n",y);
      |               ^
a.cc:17:9: error: expected unqualified-id before 'return'
   17 |         return 0;
      |         ^~~~~~
a.cc:18:1: error: expected declaration before '}' token
   18 | }
      | ^
Language: C++

#include<bits/stdc++.h>
#include <cassert>
#include <algorithm>
#include <functional>
using namespace std;
int main() {
  	//a≤x≤b,c≤y≤d を満たす整数 x,y について、x×y の最大値はいくつですか。
	int a;
  	int b;
	int c;
	int d;
	cin >> a >> b >> c >> d;
	cout << std::max({a*c,a*d,b*c,b*d}, std::greater<int>()); << "\n";
}

Compiler output:
a.cc: In function 'int main()':
a.cc:13:67: error: expected primary-expression before '<<' token
   13 |         cout << std::max({a*c,a*d,b*c,b*d}, std::greater<int>()); << "\n";
      |                                                                   ^~
Language: Java

import java.util.*;
import java.lang.Math;

class Main{

public static void main(String[] args){
Scanner scanner1 = new Scanner(System.in);
Scanner scanner2 = new Scanner(System.in);
int a=scanner1.nextInt();
int b=scanner1.nextInt();
int c=scanner1.nextInt();
int d=scanner1.nextInt();

int e=Math.max(a*c,Math.max(a*d,Math.max(b*c,b*d)));
System.out.print(e);

Compiler output:
Main.java:15: error: reached end of file while parsing
System.out.print(e);
                    ^
1 error
Language: C++

#include<cstdio>
#include<algorithm>
using namespace std;
int main(void)

	long long int a,b,c,d,x[4]={0},y,i;
	scanf("%d %d %d %d",&a,&b,&c,&d);
	x[0]=a*d;
	x[1]=a*c;
	x[2]=b*c;
	x[3]=b*d;
	y=x[0];
	for(i=0;i<4;i++){
		if(y<x[i]) y=x[i];
	}
	printf("%lld\n",y);
	return 0;
}


Compiler output:
a.cc:6:9: error: expected initializer before 'long'
    6 |         long long int a,b,c,d,x[4]={0},y,i;
      |         ^~~~
a.cc:6:39: error: expected unqualified-id before ',' token
    6 |         long long int a,b,c,d,x[4]={0},y,i;
      |                                       ^
a.cc:6:41: error: expected constructor, destructor, or type conversion before ',' token
    6 |         long long int a,b,c,d,x[4]={0},y,i;
      |                                         ^
a.cc:6:43: error: expected constructor, destructor, or type conversion before ';' token
    6 |         long long int a,b,c,d,x[4]={0},y,i;
      |                                           ^
a.cc:7:14: error: expected constructor, destructor, or type conversion before '(' token
    7 |         scanf("%d %d %d %d",&a,&b,&c,&d);
      |              ^
a.cc:8:9: error: 'x' does not name a type
    8 |         x[0]=a*d;
      |         ^
a.cc:9:9: error: 'x' does not name a type
    9 |         x[1]=a*c;
      |         ^
a.cc:10:9: error: 'x' does not name a type
   10 |         x[2]=b*c;
      |         ^
a.cc:11:9: error: 'x' does not name a type
   11 |         x[3]=b*d;
      |         ^
a.cc:12:9: error: 'y' does not name a type
   12 |         y=x[0];
      |         ^
a.cc:13:9: error: expected unqualified-id before 'for'
   13 |         for(i=0;i<4;i++){
      |         ^~~
a.cc:13:17: error: 'i' does not name a type
   13 |         for(i=0;i<4;i++){
      |                 ^
a.cc:13:21: error: 'i' does not name a type
   13 |         for(i=0;i<4;i++){
      |                     ^
a.cc:16:15: error: expected constructor, destructor, or type conversion before '(' token
   16 |         printf("%lld\n",y);
      |               ^
a.cc:17:9: error: expected unqualified-id before 'return'
   17 |         return 0;
      |         ^~~~~~
a.cc:18:1: error: expected declaration before '}' token
   18 | }
      | ^
Language: C++


int main(){
	long long a, b, c, d;
  cin >> a >> b >> c >> d;
  if(0<=a && 0<=b && 0<=c && 0<=d){
  	cout << b*d << endl;
  }
  if(0<=a && 0<=b && c<=0 && 0<=d){
  	cout << b*d << endl;
  }
  if(a<=0 && 0<=b && 0<=c && 0<=d){
  	cout << b*d << endl;
  }
  if(0<=a && 0<=b && c<=0 && d<=0){
  	cout << a*d << endl;
  }
  if(a<=0 && b<=0 && 0<=c && 0<=d){
  	cout << b*c << endl;
  }
  if(a<=0 && 0<=b && c<=0 && 0<=d){
  	cout << a*c << endl;
  }
  if(a<=0 && 0<=b && c<=0 && d<=0){
  	cout << a*c << endl;
  }
  if(a<=0 && b<=0 && c<=0 && 0<=d){
  	cout << a*c << endl;
  }
  if(a<=0 && b<=0 && c<=0 && d<=0){
  	cout << a*c << endl;
  }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:4:3: error: 'cin' was not declared in this scope
    4 |   cin >> a >> b >> c >> d;
      |   ^~~
a.cc:6:9: error: 'cout' was not declared in this scope
    6 |         cout << b*d << endl;
      |         ^~~~
a.cc:6:24: error: 'endl' was not declared in this scope
    6 |         cout << b*d << endl;
      |                        ^~~~
a.cc:9:9: error: 'cout' was not declared in this scope
    9 |         cout << b*d << endl;
      |         ^~~~
a.cc:9:24: error: 'endl' was not declared in this scope
    9 |         cout << b*d << endl;
      |                        ^~~~
a.cc:12:9: error: 'cout' was not declared in this scope
   12 |         cout << b*d << endl;
      |         ^~~~
a.cc:12:24: error: 'endl' was not declared in this scope
   12 |         cout << b*d << endl;
      |                        ^~~~
a.cc:15:9: error: 'cout' was not declared in this scope
   15 |         cout << a*d << endl;
      |         ^~~~
a.cc:15:24: error: 'endl' was not declared in this scope
   15 |         cout << a*d << endl;
      |                        ^~~~
a.cc:18:9: error: 'cout' was not declared in this scope
   18 |         cout << b*c << endl;
      |         ^~~~
a.cc:18:24: error: 'endl' was not declared in this scope
   18 |         cout << b*c << endl;
      |                        ^~~~
a.cc:21:9: error: 'cout' was not declared in this scope
   21 |         cout << a*c << endl;
      |         ^~~~
a.cc:21:24: error: 'endl' was not declared in this scope
   21 |         cout << a*c << endl;
      |                        ^~~~
a.cc:24:9: error: 'cout' was not declared in this scope
   24 |         cout << a*c << endl;
      |         ^~~~
a.cc:24:24: error: 'endl' was not declared in this scope
   24 |         cout << a*c << endl;
      |                        ^~~~
a.cc:27:9: error: 'cout' was not declared in this scope
   27 |         cout << a*c << endl;
      |         ^~~~
a.cc:27:24: error: 'endl' was not declared in this scope
   27 |         cout << a*c << endl;
      |                        ^~~~
a.cc:30:9: error: 'cout' was not declared in this scope
   30 |         cout << a*c << endl;
      |         ^~~~
a.cc:30:24: error: 'endl' was not declared in this scope
   30 |         cout << a*c << endl;
      |                        ^~~~
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main()
{
  long long int a[4],ans;
  for(int i=0;i<4;i++)
  {
    for(int j=i+1;j<4;j++)
    {
      ans=max(ans,a[i]*a[j]);
    }
  }
  if(ans<0)
  {
    if((0>=a && 0<=b) || (0>=c && 0<=d))
      ans=0;
  }
  cout<<ans;
  return 0;
}
    
    

Compiler output:
a.cc: In function 'int main()':
a.cc:15:10: error: ordered comparison of pointer with integer zero ('int' and 'long long int*')
   15 |     if((0>=a && 0<=b) || (0>=c && 0<=d))
      |         ~^~~
a.cc:15:20: error: 'b' was not declared in this scope
   15 |     if((0>=a && 0<=b) || (0>=c && 0<=d))
      |                    ^
a.cc:15:30: error: 'c' was not declared in this scope
   15 |     if((0>=a && 0<=b) || (0>=c && 0<=d))
      |                              ^
a.cc:15:38: error: 'd' was not declared in this scope
   15 |     if((0>=a && 0<=b) || (0>=c && 0<=d))
      |                                      ^
Language: C++


void solve(long long a, long long b, long long c, long long d)
{
  LL ans = max(a * c, a * d);
  chmax(ans, max(b * d, b * c));
  cout << ans << endl;
}

Compiler output:
a.cc: In function 'void solve(long long int, long long int, long long int, long long int)':
a.cc:4:3: error: 'LL' was not declared in this scope
    4 |   LL ans = max(a * c, a * d);
      |   ^~
a.cc:5:9: error: 'ans' was not declared in this scope
    5 |   chmax(ans, max(b * d, b * c));
      |         ^~~
a.cc:5:14: error: 'max' was not declared in this scope
    5 |   chmax(ans, max(b * d, b * c));
      |              ^~~
a.cc:5:3: error: 'chmax' was not declared in this scope
    5 |   chmax(ans, max(b * d, b * c));
      |   ^~~~~
a.cc:6:3: error: 'cout' was not declared in this scope
    6 |   cout << ans << endl;
      |   ^~~~
a.cc:6:18: error: 'endl' was not declared in this scope
    6 |   cout << ans << endl;
      |                  ^~~~
Language: C++

#include <iostream> 

 using namespace std;
int main() 
{ 
  long long int a,b,c,d;
  cin>>a>>b>>c>>d;

  ll ans=LLONG_MIN;
  if((a<=0&&b>=0)||(c<=0&&d>=0))ans=0;
  ans=max({a*c,a*d,b*c,b*d,ans});
  //cout<<ans<<'\n';

  cout<<ans;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:9:3: error: 'll' was not declared in this scope
    9 |   ll ans=LLONG_MIN;
      |   ^~
a.cc:10:33: error: 'ans' was not declared in this scope; did you mean 'abs'?
   10 |   if((a<=0&&b>=0)||(c<=0&&d>=0))ans=0;
      |                                 ^~~
      |                                 abs
a.cc:11:3: error: 'ans' was not declared in this scope; did you mean 'abs'?
   11 |   ans=max({a*c,a*d,b*c,b*d,ans});
      |   ^~~
      |   abs
a.cc:11:10: error: no matching function for call to 'max(<brace-enclosed initializer list>)'
   11 |   ans=max({a*c,a*d,b*c,b*d,ans});
      |       ~~~^~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/string:51,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   candidate expects 2 arguments, 1 provided
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 1 provided
Language: C++

#include<bits/stdc++.h>
using namespace std;

long long a,b,c,d;

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	cin>>a>>b>>c>>d;
	cout<<max(max(max(max(a*b,a*c),max(a*d,b*c)),max(b*d,c*d)),max(max(a*a,b*b),max(c*c,d*d))<<endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:11:98: error: invalid operands of types 'const long long int' and '<unresolved overloaded function type>' to binary 'operator<<'
   11 |         cout<<max(max(max(max(a*b,a*c),max(a*d,b*c)),max(b*d,c*d)),max(max(a*a,b*b),max(c*c,d*d))<<endl;
      |                                                                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
Language: C++

#include<bits/stdc++.h>

using namespace std;

int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0); 
	long long a,b,c,d,p1,p2,p4,p3;
  	cin>>a>>b>>c>>d;
    p1=a*c;
  	p2=b*d;
	p3=a*d;
  	p4=b*c;
  	if((a<0 && b>0) ||(c<0 && d>0)
       {
         if(0>p1 && 0>p2 && 0>p3 && 0>p4)
         cout<<"0";
       }
  	if(p1>p2 && p1>p3 && p1>p4)
      cout<<p1;
  	else if(p2>p1 && p2>p3 && p2>p4)
      cout<<p2;
  	else if(p3>p2 && p3>p1 && p3>p4)
      cout<<p3;
  	else if(p4>p2 && p4>p3 && p4>p1)
      cout<<p4; 
	return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:15:39: error: expected ';' before '{' token
   15 |         if((a<0 && b>0) ||(c<0 && d>0)
      |                                       ^
      |                                       ;
   16 |        {
      |        ~                               
a.cc:20:9: error: expected primary-expression before 'if'
   20 |         if(p1>p2 && p1>p3 && p1>p4)
      |         ^~
a.cc:19:9: error: expected ')' before 'if'
   19 |        }
      |         ^
      |         )
   20 |         if(p1>p2 && p1>p3 && p1>p4)
      |         ~~
a.cc:15:11: note: to match this '('
   15 |         if((a<0 && b>0) ||(c<0 && d>0)
      |           ^
Language: C++

#include<bits/stdc++.h>
using namespace std;

int main(){
	int a,b,c,d;
	cin >> a >> b >> c >> d;
	vector<int> prod;
	int i;
	prod[0] = a * c;
	prod[1] = a * d;
	prod[2] = b * c;
	prod[3] = b * d;
	int max=prod[0];
	cout << max(max(prod[0],prod[1]),max(prod[2],prod[3])) << endl;
	/*for(i=0;i<4;i++){
		if(max>=prod[i]){
			max = prod[i];
		}
	}
	cout << max << endl;
	*/
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:14:24: error: 'max' cannot be used as a function
   14 |         cout << max(max(prod[0],prod[1]),max(prod[2],prod[3])) << endl;
      |                     ~~~^~~~~~~~~~~~~~~~~
a.cc:14:45: error: 'max' cannot be used as a function
   14 |         cout << max(max(prod[0],prod[1]),max(prod[2],prod[3])) << endl;
      |                                          ~~~^~~~~~~~~~~~~~~~~
a.cc:14:62: error: 'max' cannot be used as a function
   14 |         cout << max(max(prod[0],prod[1]),max(prod[2],prod[3])) << endl;
      |                                                              ^
Language: C++

#include<bits/stdc++.h>
using namespace std;

int main(){
	int a,b,c,d;
	cin >> a >> b >> c >> d;
	vector<int> prod;
	int i;
	prod[0] = a * c;
	prod[1] = a * d;
	prod[2] = b * c;
	prod[3] = b * d;
	int max=prod[0];
	cout << max(max(prod[0],prod[1]),max(prod[2],prod[3]))
	/*for(i=0;i<4;i++){
		if(max>=prod[i]){
			max = prod[i];
		}
	}
	cout << max << endl;
	*/
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:14:24: error: 'max' cannot be used as a function
   14 |         cout << max(max(prod[0],prod[1]),max(prod[2],prod[3]))
      |                     ~~~^~~~~~~~~~~~~~~~~
a.cc:14:45: error: 'max' cannot be used as a function
   14 |         cout << max(max(prod[0],prod[1]),max(prod[2],prod[3]))
      |                                          ~~~^~~~~~~~~~~~~~~~~
a.cc:14:62: error: 'max' cannot be used as a function
   14 |         cout << max(max(prod[0],prod[1]),max(prod[2],prod[3]))
      |                                                              ^
Language: C++

#include<bits/stdc++.h>

using namespace std;

int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0); 
	long long a,b,c,d,p1,p2,p4,p3;
  	cin>>a>>b>>c>>d;
    p1=a*c;
  	p2=b*d;
	p3=a*d;
  	p4=b*c;
  	if((a<0 && b>0) ||(c<0 && d>0)
       {
         if{0>p1 && 0>p2 && 0>p3 && 0>p4)
         cout<<"0";
       }
  	if(p1>p2 && p1>p3 && p1>p4)
      cout<<p1;
  	else if(p2>p1 && p2>p3 && p2>p4)
      cout<<p2;
  	else if(p3>p2 && p3>p1 && p3>p4)
      cout<<p3;
  	else if(p4>p2 && p4>p3 && p4>p1)
      cout<<p4; 
	return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:15:39: error: expected ')' before '{' token
   15 |         if((a<0 && b>0) ||(c<0 && d>0)
      |           ~                           ^
      |                                       )
   16 |        {
      |        ~                               
a.cc:29:2: error: expected statement at end of input
   29 | }
      |  ^
a.cc:29:2: error: expected '}' at end of input
a.cc:6:1: note: to match this '{'
    6 | {
      | ^
Language: C++

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

#include <boost/multiprecision/cpp_dec_float.hpp>
#include <boost/multiprecision/cpp_int.hpp>
namespace mp = boost::multiprecision;
// 任意長整数型
using Bint = mp::cpp_int;
// 仮数部が1024ビットの浮動小数点数型(TLEしたら小さくする)
using Real = mp::number<mp::cpp_dec_float<1024>>;

int main(){
    Bint a, b, c, d;
    vector<Bint> ans;

    cin >> a >> b >> c >> d;

    ans.push_back(a * c);
    ans.push_back(a * d);
    ans.push_back(b * c);
    ans.push_back(b * d);

    sort(ans.begin(), ans.end(), greater<int>());

    cout << ans[0] << endl;
    return 0;
}


Compiler output:
a.cc:6:10: fatal error: boost/multiprecision/cpp_dec_float.hpp: No such file or directory
    6 | #include <boost/multiprecision/cpp_dec_float.hpp>
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
Language: C

#include<bits/stdc++.h>

#define Bye return 0
#define ll long long

using namespace std;

void solve(){
    ll a, b, c, d; cin>>a>>b>>c>>d;

    ll maxi = max({a*c, a*d, b*c, b*d});

    cout<<maxi<<endl;
}

int main(){
    solve();
    Bye;
}

Compiler output:
main.c:1:9: fatal error: bits/stdc++.h: No such file or directory
    1 | #include<bits/stdc++.h>
      |         ^~~~~~~~~~~~~~~
compilation terminated.
Language: C++

#include<iostream>
#include<algorithm>
using namespace std;
int main()
{
  long a[4],b[4];
  cin>>a[0]>>a[1]>>a[2]>>a[3];
    long b[0]=a[1]*a[3];
  long b[1]=a[0]*a[2];
  long b[2]=a[0]*a[3];
  long b[3]=a[1]*a[2];
  sort(b,b+4);
  cout<<b[3];
        
  
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:10: error: conflicting declaration 'long int b [0]'
    8 |     long b[0]=a[1]*a[3];
      |          ^
a.cc:6:13: note: previous declaration as 'long int b [4]'
    6 |   long a[4],b[4];
      |             ^
a.cc:9:8: error: conflicting declaration 'long int b [1]'
    9 |   long b[1]=a[0]*a[2];
      |        ^
a.cc:6:13: note: previous declaration as 'long int b [4]'
    6 |   long a[4],b[4];
      |             ^
a.cc:10:8: error: conflicting declaration 'long int b [2]'
   10 |   long b[2]=a[0]*a[3];
      |        ^
a.cc:6:13: note: previous declaration as 'long int b [4]'
    6 |   long a[4],b[4];
      |             ^
a.cc:11:8: error: conflicting declaration 'long int b [3]'
   11 |   long b[3]=a[1]*a[2];
      |        ^
a.cc:6:13: note: previous declaration as 'long int b [4]'
    6 |   long a[4],b[4];
      |             ^
Language: C++

#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
using namespace std;

int main()
{
	long long a, b, c, d;
	cin >> a >> b >> c >> d;
	long long ans1 = a * c, ans2 = a * d, ans3 = b * c, ans4 = b * d;
	long long lol = max(ans1, ans2);
	long long kek = max(max(ans3, ans4),ans5);
	long long ans = max(lol, kek);
	cout << max(lol,kek);
}

Compiler output:
a.cc: In function 'int main()':
a.cc:13:45: error: 'ans5' was not declared in this scope; did you mean 'ans4'?
   13 |         long long kek = max(max(ans3, ans4),ans5);
      |                                             ^~~~
      |                                             ans4
Language: C++

#include <bits/stdc++.h>
using namespace std;
#define int long long int
#define pb  push_back
int32_t main()
{
       int a,b,c,d;
       cin>>a>>b>>c>>d;
       if(b*c<a*d)
       cout<<a*d;
       else if(b*c>a*d)
       cout<<b*c;
       else if(a*c>b*d)
       cout<<a*c;
       else
       cout<<b*d
       return 0;
}

Compiler output:
a.cc: In function 'int32_t main()':
a.cc:16:17: error: expected ';' before 'return'
   16 |        cout<<b*d
      |                 ^
      |                 ;
   17 |        return 0;
      |        ~~~~~~
Language: C++

#include <cstdio>
#include <algorithm>
#include <stack>
#include <queue>
#include <deque>
#include <vector>
#include <string>
#include <string.h>
#include <cstdlib>
#include <ctime>
#include <cmath>
#include <map>
#include <set>
#include <iostream>
#include <sstream>
#include <numeric>
#include <cctype>
#include <bitset>
#include <cassert>

using namespace std;

long long a, b, c,

int main() {
    cin >> a >> b >> c >> d;
    cout << max(max(a * c, b * d), max(a * d, b * c)) << endl;
    return 0;
}

Compiler output:
a.cc:25:1: error: expected unqualified-id before 'int'
   25 | int main() {
      | ^~~
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main()
  {
  
  long long int a,b,c,d,x,y;
  cin>>a>>b>>c>>d;
  long long int l=a*c;
 long long  int k=a*d;
 long long  int x=b*c;
 long long  int y=b*d;
  long long int j=a*d;
  if((max(l,k)>max(x,y)) and max(x,y)>j)
     {
      cout<<max(l,k)<<endl; 
       
       }
    else if((max(x,y)>max(l,k)) and max(l,k)>j)
  {cout<<max(x,y)<<endl;
   
   }
            else cout<<j<<endl;
  
  }


Compiler output:
a.cc: In function 'int main()':
a.cc:10:17: error: redeclaration of 'long long int x'
   10 |  long long  int x=b*c;
      |                 ^
a.cc:6:25: note: 'long long int x' previously declared here
    6 |   long long int a,b,c,d,x,y;
      |                         ^
a.cc:11:17: error: redeclaration of 'long long int y'
   11 |  long long  int y=b*d;
      |                 ^
a.cc:6:27: note: 'long long int y' previously declared here
    6 |   long long int a,b,c,d,x,y;
      |                           ^
Language: C++

#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); ++i)
using namespace std;
using ll = long long;
using P = pair<int,int>;

int main() {
  long long a, b, c, d, max1, max2;
  
  cin >> a >> b >> c >> d;
  
  max1 = a*c;
  if(a*d>max1) max1=a*d;
  else if(b*c>max1) max1=b*c;
  else max1=b*d;
  


Compiler output:
a.cc: In function 'int main()':
a.cc:15:17: error: expected '}' at end of input
   15 |   else max1=b*d;
      |                 ^
a.cc:7:12: note: to match this '{'
    7 | int main() {
      |            ^
Language: C++

#include <iostream>
 
int main(){
  int a, b, c, d;
  
  std::cin >> a >> b >> c >> d;
  
  if ( b == 0 && d == 0 ){
    std::cout << a*c;
  }
  else if ( b > 0 && d == 0 ) {
    if ( a >= 0 ) {
      std::cout << 0;
    }
    else{
      std::cout << a*c;
    }
  }
  else if ( b == 0 && d > 0 ) {
    if ( c >= 0 ) {
      std::cout << 0;
    }
    else{
      std::cout << a*c;
    }    
  }
  else if ( b < 0 && d == 0 ) {
    std::cout << a*c;
  }
  else if ( b == 0 && d < 0 ) {
    std::cout << a*c;
  }
  else if ( b > 0 && d > 0 ) {
    std::cout << b*d;
  }
  else if ( b < 0 && d > 0 ) {
    if ( c < 0 ) {
      std::cout << a*c;
    }
    else if ( c == 0 ) {
      std::cout << 0;
    }
    else{
      std::cout << b*c;
    }    
  }
  else if ( b > 0 && d < 0 ) {
    if ( a < 0 ) {
      std::cout << a*c;
    }
    else if ( a == 0 ) {
      std::cout << 0;
    }
    else{
      std::cout << a*d;
    }        
  }
    
  }
 
}

Compiler output:
a.cc:61:1: error: expected declaration before '}' token
   61 | }
      | ^
Language: C++

#include <iostream>
using namespace std;
 
int main() {
  int A, B, C, D;
  cin >> A >> B >> C >> D;
  if (A <= C && B <= D){
    if (A < 0 && C < 0 && B >= 0 && D >= 0) {
		if (A * C <= B * D){
          cout << B * D << endl;
        }
      	else{
          cout << A * C << endl;
        }
  	}
    else if (A <= 0 && D <= 0){
      cout << B * D << endl;
  	}
    else if (B <= 0 && C <= 0){
      cout << B * D << endl;
  	}
    else{
      cout << A * C << endl;
    }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:25:2: error: expected '}' at end of input
   25 | }
      |  ^
a.cc:4:12: note: to match this '{'
    4 | int main() {
      |            ^
Language: C

#include <stdio.h>
#include <math.h>
#include <stdlib.h>

int main(){
    int a,b,c,d;
    int output;
    scanf("%d %d %d %d", &a, &b, &c, &d);
    
    if(a<b && c<d){
    if(abs(a)>=abs(b) && abs(c)>=abs(d)){
        printf("%d %d\n", abs(a), abs(c));
        output = abs(a)*abs(c);
    }
    else if(abs(a)=<abs(b) && abs(c)=<abs(d)){
        printf("%d %d\n", abs(b), abs(d));
        output = abs(b)*abs(d);
    }
    else if(abs(a)>=abs(b) && abs(c)=<abs(d)) {
        printf("%d %d\n", abs(a), abs(d));
        output = abs(a)*abs(d);
    }
    else if(abs(a)=<abs(b) && abs(c)>=abs(d)) {
        printf("%d %d\n", abs(b), abs(c));
        output = abs(b)*abs(c);
    }
    }
    //printf("output:%1.1f\n", output);
    printf("%d\n", output);

    return 0;
}


Compiler output:
main.c: In function 'main':
main.c:15:20: error: expected expression before '<' token
   15 |     else if(abs(a)=<abs(b) && abs(c)=<abs(d)){
      |                    ^
main.c:19:38: error: expected expression before '<' token
   19 |     else if(abs(a)>=abs(b) && abs(c)=<abs(d)) {
      |                                      ^
main.c:23:20: error: expected expression before '<' token
   23 |     else if(abs(a)=<abs(b) && abs(c)>=abs(d)) {
      |                    ^
Language: C++

#include <bits/stdc++.h>
uding namespace std;

int main(){
  long long a[2],b[2],i,j;
    
  for(i=0;i<2;i++)
    cin >> a[i];
  for(i=0;i<2;i++)
    cin >> b[i];
  
  vector<long long>v;
  for(i=0;i<2;i++)
    for(j=0;j<2;j++)
      v.push_back(a[i]*b[j]);
  
  sort(v.begin(),v.end());
  cout << v[v.size()-1] <<"\n";
  
  return 0;
}

Compiler output:
a.cc:2:1: error: 'uding' does not name a type
    2 | uding namespace std;
      | ^~~~~
a.cc: In function 'int main()':
a.cc:8:5: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    8 |     cin >> a[i];
      |     ^~~
      |     std::cin
In file included from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:146,
                 from a.cc:1:
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:10:5: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
   10 |     cin >> b[i];
      |     ^~~
      |     std::cin
/usr/include/c++/14/iostream:62:18: note: 'std::cin' declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
a.cc:12:3: error: 'vector' was not declared in this scope
   12 |   vector<long long>v;
      |   ^~~~~~
a.cc:12:3: note: suggested alternatives:
In file included from /usr/include/c++/14/vector:66,
                 from /usr/include/c++/14/functional:64,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:53:
/usr/include/c++/14/bits/stl_vector.h:428:11: note:   'std::vector'
  428 |     class vector : protected _Vector_base<_Tp, _Alloc>
      |           ^~~~~~
/usr/include/c++/14/vector:93:13: note:   'std::pmr::vector'
   93 |       using vector = std::vector<_Tp, polymorphic_allocator<_Tp>>;
      |             ^~~~~~
a.cc:12:10: error: expected primary-expression before 'long'
   12 |   vector<long long>v;
      |          ^~~~
a.cc:15:7: error: 'v' was not declared in this scope
   15 |       v.push_back(a[i]*b[j]);
      |       ^
a.cc:17:8: error: 'v' was not declared in this scope
   17 |   sort(v.begin(),v.end());
      |        ^
a.cc:17:3: error: 'sort' was not declared in this scope; did you mean 'std::sort'?
   17 |   sort(v.begin(),v.end());
      |   ^~~~
      |   std::sort
In file included from /usr/include/c++/14/algorithm:86,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51:
/usr/include/c++/14/pstl/glue_algorithm_defs.h:296:1: note: 'std::sort' declared here
  296 | sort(_ExecutionPolicy&& __exec, _RandomAccessIterator __first, _RandomAccessIterator __last);
      | ^~~~
a.cc:18:3: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
   18 |   cout << v[v.size()-1] <<"\n";
      |   ^~~~
      |   std::cout
/usr/include/c++/14/iostream:63:18: note: 'std::cout' declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~
Language: C

#include<stdio.h>
#include<algorithm>
using namespace std;
int main(void)
{
  long long a,b,c,d;
  scanf("%lld%lld%lld%lld",&a,&b,&c,&d);
  printf("%lld\n",max(a*c,max(a*d,max(b*c,b*d))));
  return 0;
}

Compiler output:
main.c:2:9: fatal error: algorithm: No such file or directory
    2 | #include<algorithm>
      |         ^~~~~~~~~~~
compilation terminated.
Language: C

#include <stdio.h>
int main(void)
{
  int a,b,c,d;
  scanf("%d %d %d %d", &a, &b, &c, &d);
  int ac = a * c;
  int ad = a * d;
  int bc = b * c;
  int bd = b * d;
  if (ac > ad)
  {
    if (ac > bc)
    {
      if (ac > bd)
      {
        printf("%d", ab);
      }
      else
      {
        printf("%d", bd);
      }
    }
    else
    {
      if (bc > bd)
      {
        printf("%d", bc);
      }
      else
      {
        printf("%d", bd);
      }
    }
  }
  else
  {
    if (ad > bc)
    {
      if (ad > bd)
      {
        printf("%d", ad);
      }
      else
      {
        printf("%d", bd);
      }
    }
    else
    {
      if (bc > bd)
      {
        printf("%d", bc);
      }
      else
      {
        printf("%d", bd);
      }
    }
  }
  return 0;
}

Compiler output:
main.c: In function 'main':
main.c:16:22: error: 'ab' undeclared (first use in this function); did you mean 'ad'?
   16 |         printf("%d", ab);
      |                      ^~
      |                      ad
main.c:16:22: note: each undeclared identifier is reported only once for each function it appears in
Language: C++

#include <bits/stdc++.h>
using namespace std;
//5



int main() {
  int a,b,c,d,;
  cin >> a >> b >> c >> d;
  cout << max(a,b) * max(c,d) << endl;
  
    
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:15: error: expected unqualified-id before ';' token
    8 |   int a,b,c,d,;
      |               ^
Language: C++

#include <stdio.h>

int max4(int r, int s, int t, int u)
{
   int max = r;
  
  if (s > max) max = s;
  if (t > max) max = t;
  if (u > max) max = u;
  return max;
}

int main(void)
{
    int a, b, c, d;
    scanf("%d", &a);
    scanf("%d", &b);
    scanf("%d", &c);
    scanf("%d", &d);
  
    int r, s, t, u;
    r = a * c;
    s = a * d;
    t = b * c;
    u = b * d;
  
    printf("%d", max4(r,s,t,u);

	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:27:31: error: expected ')' before ';' token
   27 |     printf("%d", max4(r,s,t,u);
      |           ~                   ^
      |                               )
Language: C++

#include <bits/stdc++.h>
using namespace std;

int main(){
  int a, b, c, d;
  cin >> a >> b >> c >> d;
  
  if(b => 0 && d => 0){
    if(a <= 0 && c <= 0)
      cout << max(a*c, b*d) << endl;
    else
      cout << b * d << endl;
  }
  else if(a >= 0 && d <= 0)
    cout << a * d << endl;
  else if(b <= 0 && c >= 0)
    cout << b * c << endl;
  else if(a <= 0 && c <= 0)
    cout << a * c << endl;
  
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:9: error: expected primary-expression before '>' token
    8 |   if(b => 0 && d => 0){
      |         ^
a.cc:8:19: error: expected primary-expression before '>' token
    8 |   if(b => 0 && d => 0){
      |                   ^
Language: C

#include<stdio.h>
#include<stdlib.h>

int main(){
  long long int a,b,c,d;
  long long int ans;
  scanf("%lld %lld %lld %lld",&a,&b,&c,&d);
  ans=a*c;
  for(long long int i=a; i<=b,i++){
    for(long long int j=c;j<=d;j++){
      int s=i*j;
      if(s>ans){
        ans=s;
      }
      else
    }
  }
  printf("%lld",ans);
}

Compiler output:
main.c: In function 'main':
main.c:9:34: error: expected ';' before ')' token
    9 |   for(long long int i=a; i<=b,i++){
      |                                  ^
      |                                  ;
main.c:16:5: error: expected expression before '}' token
   16 |     }
      |     ^
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main()
  {
  
  long long int a,b,c,d,x,y;
  cin>>a>>b>>c>>d;
  long long int l=a*c;
 long long  int k=a*d;
 long long  int x=b*c;
 long long  int y=b*d;
  long long int j=a*d;
  if((max(l,k)>max(x,y)) and max(x,y)>j)
     {
      cout<<max(l,k)<<endl; 
       
       }
    else if((max(x,y)>max(l,k)) and max(l,k)>j)
  {cout<<max(x,y)<<endl;
   
   }
            else cout<<j<<endl;
  
  }

Compiler output:
a.cc: In function 'int main()':
a.cc:10:17: error: redeclaration of 'long long int x'
   10 |  long long  int x=b*c;
      |                 ^
a.cc:6:25: note: 'long long int x' previously declared here
    6 |   long long int a,b,c,d,x,y;
      |                         ^
a.cc:11:17: error: redeclaration of 'long long int y'
   11 |  long long  int y=b*d;
      |                 ^
a.cc:6:27: note: 'long long int y' previously declared here
    6 |   long long int a,b,c,d,x,y;
      |                           ^
Language: C++

#include <bits/stdc++.h>
#include <algorithm>
using namespace std;

int main() {
    int a, b, c, d;
    cin >> a >> b >> c >> d;

    int e[] = {a*c, a*d, b*c, b*d};
    int n = sizeof(arr) / sizeof(arr[0]);

    cout << max_element(e, e + n) << endl;
    return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:10:20: error: 'arr' was not declared in this scope
   10 |     int n = sizeof(arr) / sizeof(arr[0]);
      |                    ^~~
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main()
{
  long long int a,b,c,d;
  cin>>a>>b>>c>>d;
    p=a*c;
  q=a*d;
  r=b*c;
  s=b*d;
 long long int t=max(p,q);
 long long  int g=max(r,s);
  cout<<max(t,g);
    
}


Compiler output:
a.cc: In function 'int main()':
a.cc:7:5: error: 'p' was not declared in this scope
    7 |     p=a*c;
      |     ^
a.cc:8:3: error: 'q' was not declared in this scope
    8 |   q=a*d;
      |   ^
a.cc:9:3: error: 'r' was not declared in this scope
    9 |   r=b*c;
      |   ^
a.cc:10:3: error: 's' was not declared in this scope
   10 |   s=b*d;
      |   ^