answer.code: In function ‘int main()’:
answer.code:16:2: error: expected ‘;’ before ‘int’
   16 | 2
      |  ^
      |  ;
   17 |     int s;
      |     ~~~
answer.code:19:9: error: ‘s’ was not declared in this scope
   19 |         s=a[0]*a[3];
      |         ^
answer.code:21:9: error: ‘s’ was not declared in this scope
   21 |         s=a[1]*a[3];
      |         ^
answer.code:23:9: error: ‘s’ was not declared in this scope
   23 |         s=a[1]*a[2];
      |         ^
answer.code:25:9: error: ‘s’ was not declared in this scope
   25 |         s=a[1]*a[3];
      |         ^
answer.code:26:11: error: ‘s’ was not declared in this scope
   26 |     cout<<s<<endl;
      |           ^