View Compilation Error

0_0_35092168_1367.cpp: In function 'int main()':
0_0_35092168_1367.cpp:6:22: error: 'scanf' was not declared in this scope
  while(~scanf("%d",&n)){
                      ^
0_0_35092168_1367.cpp:7:11: error: 'getchar' was not declared in this scope
   getchar();
           ^
0_0_35092168_1367.cpp:10:12: error: 'gets' was not declared in this scope
    gets(str);
            ^
0_0_35092168_1367.cpp:17:38: error: 'printf' was not declared in this scope
     printf("%c:%d\n",letter[k],num[k]);
                                      ^
0_0_35092168_1367.cpp:19:16: error: 'printf' was not declared in this scope
     printf("\n");
                ^