View Compilation Error

0_0_13142880_22629.cpp: In function 'int main(int, char**)':
0_0_13142880_22629.cpp:4:15: error: 'scanf' was not declared in this scope
  scanf("%d",&t);
               ^
0_0_13142880_22629.cpp:14:19: error: 'printf' was not declared in this scope
    printf("%d\n",i);
                   ^