Language: C++

#include<bits/stdc++.h>

#define pb push_back
#define ppb pop_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define sz(x) (int)(x).size()
#define ll long long
#define bit __builtin_popcountll
#define sqr(x) (x) * (x)
#define forit(it,S) for(__typeof((S).begin()) it = (S).begin(); it != (S).end(); it++)
#define debug(x) cout << #x <<" = " << x << endl
#define forn(i, n) for(int i = 0 ; (i) < (n) ; ++i)
#define printvpair(v) for(int i = 0 ; (i) < (v.size()) ; ++i) cout << v[i].first  <<" " << v[i].second << endl;
#define printv(v) for(int i = 0 ; (i) < (v.size()) ; ++i) cout << v[i] << " "; cout << endl;

using namespace std;

typedef pair<int, int> pii;

const double eps = 1e-9;
const double pi = acos(-1.0);
const int INF = 1000000000;

const int dx[4] = {0,  0, 1, -1};
const int dy[4] = {1, -1, 0,  0};

const int N = 100001;
int a[N];
int a,b,c,d;
int main() {
	ios_base::sync_with_stdio(0);
	cin >> a >> b >> c >> d;
	if (a * b >= c * d)
		cout << a * b << endl;
	else
		cout << c * d << endl;
  	return 0;
}


Compiler output:
a.cc:30:5: error: conflicting declaration 'int a'
   30 | int a,b,c,d;
      |     ^
a.cc:29:5: note: previous declaration as 'int a [100001]'
   29 | int a[N];
      |     ^
a.cc: In function 'int main()':
a.cc:33:13: error: no match for 'operator>>' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'int [100001]')
   33 |         cin >> a >> b >> c >> d;
      |         ~~~ ^~ ~
      |         |      |
      |         |      int [100001]
      |         std::istream {aka std::basic_istream<char>}
In file included from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/complex:45,
                 from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127,
                 from a.cc:1:
/usr/include/c++/14/istream:170:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(bool&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  170 |       operator>>(bool& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:170:7: note:   conversion of argument 1 would be ill-formed:
a.cc:33:16: error: cannot bind non-const lvalue reference of type 'bool&' to a value of type 'int*'
   33 |         cin >> a >> b >> c >> d;
      |                ^
/usr/include/c++/14/istream:174:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(short int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  174 |       operator>>(short& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:174:7: note:   conversion of argument 1 would be ill-formed:
a.cc:33:16: error: invalid conversion from 'int*' to 'short int' [-fpermissive]
   33 |         cin >> a >> b >> c >> d;
      |                ^
      |                |
      |                int*
a.cc:33:16: error: cannot bind rvalue '(short int)((int*)(& a))' to 'short int&'
/usr/include/c++/14/istream:177:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(short unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  177 |       operator>>(unsigned short& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:177:7: note:   conversion of argument 1 would be ill-formed:
a.cc:33:16: error: invalid conversion from 'int*' to 'short unsigned int' [-fpermissive]
   33 |         cin >> a >> b >> c >> d;
      |                ^
      |                |
      |                int*
a.cc:33:16: error: cannot bind rvalue '(short unsigned int)((int*)(& a))' to 'short unsigned int&'
/usr/include/c++/14/istream:181:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  181 |       operator>>(int& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:181:7: note:   conversion of argument 1 would be ill-formed:
a.cc:33:16: error: invalid conversion from 'int*' to 'int' [-fpermissive]
   33 |         cin >> a >> b >> c >> d;
      |                ^
      |                |
      |                int*
a.cc:33:16: error: cannot bind rvalue '(int)((int*)(& a))' to 'int&'
/usr/include/c++/14/istream:184:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  184 |       operator>>(unsigned int& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:184:7: note:   conversion of argument 1 would be ill-formed:
a.cc:33:16: error: invalid conversion from 'int*' to 'unsigned int' [-fpermissive]
   33 |         cin >> a >> b >> c >> d;
      |                ^
      |                |
      |                int*
a.cc:33:16: error: cannot bind rvalue '(unsigned int)((int*)(& a))' to 'unsigned int&'
/usr/include/c++/14/istream:188:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  188 |       operator>>(long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:188:7: note:   conversion of argument 1 would be ill-formed:
a.cc:33:16: error: invalid conversion from 'int*' to 'long int' [-fpermissive]
   33 |         cin >> a >> b >> c >> d;
      |                ^
      |                |
      |                int*
a.cc:33:16: error: cannot bind rvalue '(long int)((int*)(& a))' to 'long int&'
/usr/include/c++/14/istream:192:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  192 |       operator>>(unsigned long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:192:7: note:   conversion of argument 1 would be ill-formed:
a.cc:33:16: error: invalid conversion from 'int*' to 'long unsigned int' [-fpermissive]
   33 |         cin >> a >> b >> c >> d;
      |                ^
      |                |
      |                int*
a.cc:33:16: error: cannot bind rvalue '(long unsigned int)((int*)(& a))' to 'long unsigned int&'
/usr/include/c++/14/istream:199:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  199 |       operator>>(long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:199:7: note:   conversion of argument 1 would be ill-formed:
a.cc:33:16: error: invalid conversion from 'int*' to 'long long int' [-fpermissive]
   33 |         cin >> a >> b >> c >> d;
      |                ^
      |                |
      |                int*
a.cc:33:16: error: cannot bind rvalue '(long long int)((int*)(& a))' to 'long long int&'
/usr/include/c++/14/istream:203:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  203 |       operator>>(unsigned long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:203:7: note:   conversion of argument 1 would be ill-formed:
a.cc:33:16: error: invalid conversion from 'int*' to 'long long unsigned int' [-fpermissive]
   33 |         cin >> a >> b >> c >> d;
      |                ^
      |                |
      |                int*
a.cc:33:16: error: cannot bind rvalue '(long long unsigned int)((int*)(& a))' to 'long long unsigned int&'
/usr/include/c++/14/istream:328:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(void*&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  328 |       operator>>(void*& __p)
      |       ^~~~~~~~
/usr/include/c++/14/istream:328:7: note:   conversion of argument 1 would be ill-formed:
a.cc:33:16: error: cannot bind non-const lvalue reference of type 'void*&' to an rvalue of type 'void*'
   33 |         cin >> a >> b >> c >> d;
      |                ^
/usr/include/c++/14/istream:219:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(float&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  219 |       operator>>(float& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:219:25: note:   no known conversion for argument 1 from 'int [100001]' to 'float&'
  219 |       operator>>(float& __f)
      |                  ~~~~~~~^~~
/usr/include/c++/14/istream:223:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  223 |       operator>>(double& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:223:26: note:   no known conversion for argument 1 from 'int [100001]' to 'double&'
  223 |       operator>>(double& __f)
      |                  ~~~~~~~~^~~
/usr/include/c++/14/istream:227:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  227 |       operator>>(long double& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:227:31: note:   no known conversion for argument 1 from 'int [100001]' to 'long double&'
  227 |       operator>>(long double& __f)
      |                  ~~~~~~~~~~~~~^~~
/usr/include/c++/14/istream:122:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__istream_type& (*)(__istream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  122 |       operator>>(__istream_type& (*__pf)(__istream_type&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:122:36: note:   no known conversion for argument 1 from 'int [100001]' to 'std::basic_istream<char>::__istream_type& (*)(std::basic_istream<char>::__istream_type&)' {aka 'std::basic_istream<char>& (*)(std::basic_istream<char>&)'}
  122 |       operator>>(__istream_type& (*__pf)(__istream_type&))
      |                  ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/istream:126:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__ios_type& (*)(__ios_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __ist