View Compilation Error

0_0_22820413_26384.cpp: In function 'int main()':
0_0_22820413_26384.cpp:6:18: error: 'scanf' was not declared in this scope
     scanf("%d",&t);
                  ^
0_0_22820413_26384.cpp:12:23: error: 'printf' was not declared in this scope
         { printf("0\n");
                       ^
0_0_22820413_26384.cpp:18:28: error: 'printf' was not declared in this scope
         printf("%.0f\n",sum);
                            ^