View Compilation Error

0_0_19966181_23838.cpp: In function 'int main()':
0_0_19966181_23838.cpp:23:18: error: 'scanf' was not declared in this scope
     scanf("%d",&t);
                  ^
0_0_19966181_23838.cpp:38:41: error: 'printf' was not declared in this scope
         printf("Case #%d: %d\n",ca++,ans);
                                         ^