/in/foo.cc:1:1: error: 'include' does not name a type
 include<iostream>
 ^~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:7:5: error: 'cin' was not declared in this scope
     cin >> a >> b >> c;
     ^~~
/in/foo.cc:8:23: error: 'swap' was not declared in this scope
     if(a > b)swap(a, b);
                       ^
/in/foo.cc:9:23: error: 'swap' was not declared in this scope
     if(b > c)swap(b, c);
                       ^
/in/foo.cc:13:32: error: 'printf' was not declared in this scope
         printf("%.2lf", sqrt(p));
                                ^
/in/foo.cc:14:11: error: 'cout' was not declared in this scope
     }else cout << "NO";
           ^~~~