View Compilation Error

0_0_16326851_22234.cpp: In function 'int main()':
0_0_16326851_22234.cpp:3:5: error: 'cin' was not declared in this scope
     cin>>T;
     ^
0_0_16326851_22234.cpp:5:27: error: 'scanf' was not declared in this scope
         scanf("%d%d",&n,&k);
                           ^
0_0_16326851_22234.cpp:7:21: error: 'puts' was not declared in this scope
             puts("0");
                     ^
0_0_16326851_22234.cpp:12:34: error: 'printf' was not declared in this scope
             printf("%d\n",n*n-r*r);
                                  ^
0_0_16326851_22234.cpp:14:42: error: 'printf' was not declared in this scope
             printf("%d\n",n*n-(k-r)*(k-r));
                                          ^