View Compilation Error

0_0_21391601_13285.cpp: In function 'int main()':
0_0_21391601_13285.cpp:8:15: error: 'scanf' was not declared in this scope
  scanf("%d",&t);
               ^
0_0_21391601_13285.cpp:23:14: error: 'fabs' was not declared in this scope
   if(fabs(a-b)>diff || (a+b)>(2*n-diff))
              ^
0_0_21391601_13285.cpp:25:20: error: 'printf' was not declared in this scope
    printf("Lying\n");
                    ^
0_0_21391601_13285.cpp:27:24: error: 'printf' was not declared in this scope
    printf("Not Lying\n");
                        ^