Language: C++

include<iostream>
using namespace std;

int main(){
  string a;
  cin >> a;
  if(a==SUN)cout << "7"<<endl;
  if(a==MON)cout << "6"<<endl;
  if(a==TUE)cout << "5"<<endl;
  if(a==WED)cout << "4"<<endl;
  if(a==THU)cout << "3"<<endl;
  if(a==FRI)cout << "2"<<endl;
  if(a==SAT)cout << "1"<<endl;
}

Compiler output:
a.cc:1:1: error: 'include' does not name a type
    1 | include<iostream>
      | ^~~~~~~
a.cc: In function 'int main()':
a.cc:5:3: error: 'string' was not declared in this scope
    5 |   string a;
      |   ^~~~~~
a.cc:6:3: error: 'cin' was not declared in this scope
    6 |   cin >> a;
      |   ^~~
a.cc:6:10: error: 'a' was not declared in this scope
    6 |   cin >> a;
      |          ^
a.cc:7:9: error: 'SUN' was not declared in this scope
    7 |   if(a==SUN)cout << "7"<<endl;
      |         ^~~
a.cc:7:13: error: 'cout' was not declared in this scope
    7 |   if(a==SUN)cout << "7"<<endl;
      |             ^~~~
a.cc:7:26: error: 'endl' was not declared in this scope
    7 |   if(a==SUN)cout << "7"<<endl;
      |                          ^~~~
a.cc:8:9: error: 'MON' was not declared in this scope
    8 |   if(a==MON)cout << "6"<<endl;
      |         ^~~
a.cc:8:13: error: 'cout' was not declared in this scope
    8 |   if(a==MON)cout << "6"<<endl;
      |             ^~~~
a.cc:8:26: error: 'endl' was not declared in this scope
    8 |   if(a==MON)cout << "6"<<endl;
      |                          ^~~~
a.cc:9:9: error: 'TUE' was not declared in this scope
    9 |   if(a==TUE)cout << "5"<<endl;
      |         ^~~
a.cc:9:13: error: 'cout' was not declared in this scope
    9 |   if(a==TUE)cout << "5"<<endl;
      |             ^~~~
a.cc:9:26: error: 'endl' was not declared in this scope
    9 |   if(a==TUE)cout << "5"<<endl;
      |                          ^~~~
a.cc:10:9: error: 'WED' was not declared in this scope
   10 |   if(a==WED)cout << "4"<<endl;
      |         ^~~
a.cc:10:13: error: 'cout' was not declared in this scope
   10 |   if(a==WED)cout << "4"<<endl;
      |             ^~~~
a.cc:10:26: error: 'endl' was not declared in this scope
   10 |   if(a==WED)cout << "4"<<endl;
      |                          ^~~~
a.cc:11:9: error: 'THU' was not declared in this scope
   11 |   if(a==THU)cout << "3"<<endl;
      |         ^~~
a.cc:11:13: error: 'cout' was not declared in this scope
   11 |   if(a==THU)cout << "3"<<endl;
      |             ^~~~
a.cc:11:26: error: 'endl' was not declared in this scope
   11 |   if(a==THU)cout << "3"<<endl;
      |                          ^~~~
a.cc:12:9: error: 'FRI' was not declared in this scope
   12 |   if(a==FRI)cout << "2"<<endl;
      |         ^~~
a.cc:12:13: error: 'cout' was not declared in this scope
   12 |   if(a==FRI)cout << "2"<<endl;
      |             ^~~~
a.cc:12:26: error: 'endl' was not declared in this scope
   12 |   if(a==FRI)cout << "2"<<endl;
      |                          ^~~~
a.cc:13:9: error: 'SAT' was not declared in this scope
   13 |   if(a==SAT)cout << "1"<<endl;
      |         ^~~
a.cc:13:13: error: 'cout' was not declared in this scope
   13 |   if(a==SAT)cout << "1"<<endl;
      |             ^~~~
a.cc:13:26: error: 'endl' was not declared in this scope
   13 |   if(a==SAT)cout << "1"<<endl;
      |                          ^~~~