View Compilation Error

0_0_17256337_28742.cpp: In function 'int main()':
0_0_17256337_28742.cpp:21:15: error: 'scanf' was not declared in this scope
  scanf("%d",&t);
               ^
0_0_17256337_28742.cpp:29:18: error: 'printf' was not declared in this scope
   printf("%d\n",x);
                  ^