/in/foo.cc: In function 'void gcd(int, int)':
/in/foo.cc:8:18: error: return-statement with a value, in function returning 'void' [-fpermissive]
  if(y==0) return x;
                  ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:22:28: error: invalid operands of types 'void' and 'int' to binary 'operator=='
     if(i%a1==0&&gcd(i/a1,p)==1&&gcd(q,b1/i)==1) sum++;
                 ~~~~~~~~~~~^~~
/in/foo.cc:22:44: error: invalid operands of types 'void' and 'int' to binary 'operator=='
     if(i%a1==0&&gcd(i/a1,p)==1&&gcd(q,b1/i)==1) sum++;
                                 ~~~~~~~~~~~^~~
/in/foo.cc:25:28: error: invalid operands of types 'void' and 'int' to binary 'operator=='
     if(h%a1==0&&gcd(h/a1,p)==1&&gcd(q,b1/h)==1) sum++;
                 ~~~~~~~~~~~^~~
/in/foo.cc:25:44: error: invalid operands of types 'void' and 'int' to binary 'operator=='
     if(h%a1==0&&gcd(h/a1,p)==1&&gcd(q,b1/h)==1) sum++;
                                 ~~~~~~~~~~~^~~