View Compilation Error

0_0_30439485_27980.cpp: In function 'int main()':
0_0_30439485_27980.cpp:32:15: error: 'scanf' was not declared in this scope
  scanf("%d",&T);
               ^
0_0_30439485_27980.cpp:36:21: error: 'swap' was not declared in this scope
   if(x > y) swap(x,y);
                     ^
0_0_30439485_27980.cpp:40:16: error: 'printf' was not declared in this scope
    printf("0\n");
                ^
0_0_30439485_27980.cpp:47:22: error: 'printf' was not declared in this scope
   printf("%lld\n",ans);
                      ^