Language: C++

#include <bitset> 
#include <iterator> 
#include <map>
#include <queue>
#include <set>
#include<deque>
#define rep(i,n) for(ll i=0;i<(n); ++i)
#define per(i,n) for(ll i=n-1;i>=0; --i)
#define all(x) (x).begin(),(x).end()
#define _GLIBCXX_DEBUG
using namespace std;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const long long INF = 1LL << 60;
typedef long long ll;
const ll MOD = 1000000007;
ll gcd(ll a, ll b) {
	if (b == 0) return a;
	return gcd(b, a % b);
}

int main()
{
	cin.tie(0);
	ios::sync_with_stdio(false);
	string s;
	cin >> s;
	if (s == "SUN")return cout << 7 << endl,0;
	else if(s == "MON")return cout << 6 << endl, 0;
	else if(s == "TUE")return cout << 5 << endl, 0;
	else if (s == "WED")return cout << 4 << endl, 0;
	else if (s == "THU")return cout << 3 << endl, 0;
	else if (s == "FRI")return cout << 2 << endl, 0;
	else if(s == "SAT") return cout << 1 << endl, 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:24:9: error: 'cin' was not declared in this scope
   24 |         cin.tie(0);
      |         ^~~
a.cc:6:1: note: 'std::cin' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
    5 | #include <set>
  +++ |+#include <iostream>
    6 | #include<deque>
a.cc:25:14: error: incomplete type 'std::ios' {aka 'std::basic_ios<char>'} used in nested name specifier
   25 |         ios::sync_with_stdio(false);
      |              ^~~~~~~~~~~~~~~
a.cc:28:31: error: 'cout' was not declared in this scope
   28 |         if (s == "SUN")return cout << 7 << endl,0;
      |                               ^~~~
a.cc:28:31: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:28:44: error: 'endl' was not declared in this scope
   28 |         if (s == "SUN")return cout << 7 << endl,0;
      |                                            ^~~~
a.cc:6:1: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
    5 | #include <set>
  +++ |+#include <ostream>
    6 | #include<deque>
a.cc:29:35: error: 'cout' was not declared in this scope
   29 |         else if(s == "MON")return cout << 6 << endl, 0;
      |                                   ^~~~
a.cc:29:35: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:29:48: error: 'endl' was not declared in this scope
   29 |         else if(s == "MON")return cout << 6 << endl, 0;
      |                                                ^~~~
a.cc:29:48: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
a.cc:30:35: error: 'cout' was not declared in this scope
   30 |         else if(s == "TUE")return cout << 5 << endl, 0;
      |                                   ^~~~
a.cc:30:35: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:30:48: error: 'endl' was not declared in this scope
   30 |         else if(s == "TUE")return cout << 5 << endl, 0;
      |                                                ^~~~
a.cc:30:48: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
a.cc:31:36: error: 'cout' was not declared in this scope
   31 |         else if (s == "WED")return cout << 4 << endl, 0;
      |                                    ^~~~
a.cc:31:36: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:31:49: error: 'endl' was not declared in this scope
   31 |         else if (s == "WED")return cout << 4 << endl, 0;
      |                                                 ^~~~
a.cc:31:49: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
a.cc:32:36: error: 'cout' was not declared in this scope
   32 |         else if (s == "THU")return cout << 3 << endl, 0;
      |                                    ^~~~
a.cc:32:36: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:32:49: error: 'endl' was not declared in this scope
   32 |         else if (s == "THU")return cout << 3 << endl, 0;
      |                                                 ^~~~
a.cc:32:49: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
a.cc:33:36: error: 'cout' was not declared in this scope
   33 |         else if (s == "FRI")return cout << 2 << endl, 0;
      |                                    ^~~~
a.cc:33:36: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:33:49: error: 'endl' was not declared in this scope
   33 |         else if (s == "FRI")return cout << 2 << endl, 0;
      |                                                 ^~~~
a.cc:33:49: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'
a.cc:34:36: error: 'cout' was not declared in this scope
   34 |         else if(s == "SAT") return cout << 1 << endl, 0;
      |                                    ^~~~
a.cc:34:36: note: 'std::cout' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
a.cc:34:49: error: 'endl' was not declared in this scope
   34 |         else if(s == "SAT") return cout << 1 << endl, 0;
      |                                                 ^~~~
a.cc:34:49: note: 'std::endl' is defined in header '<ostream>'; this is probably fixable by adding '#include <ostream>'