View Compilation Error

0_0_23727785_3834.cpp: In function 'int main()':
0_0_23727785_3834.cpp:4:25: error: 'scanf' was not declared in this scope
     while(~scanf("%d",&n))
                         ^
0_0_23727785_3834.cpp:8:41: error: 'printf' was not declared in this scope
             printf("2^? mod %d = 1\n", n);
                                         ^
0_0_23727785_3834.cpp:17:41: error: 'printf' was not declared in this scope
         printf("2^%d mod %d = 1\n", k, n);
                                         ^