View Compilation Error

0_0_24543614_17098.cpp: In function 'int main()':
0_0_24543614_17098.cpp:7:15: error: 'scanf' was not declared in this scope
  scanf("%d",&n);
               ^
0_0_24543614_17098.cpp:8:10: error: 'getchar' was not declared in this scope
  getchar();
          ^
0_0_24543614_17098.cpp:12:9: error: 'gets' was not declared in this scope
   gets(a);
         ^
0_0_24543614_17098.cpp:18:26: error: 'printf' was not declared in this scope
   if(mark) printf("yes\n");
                          ^
0_0_24543614_17098.cpp:19:22: error: 'printf' was not declared in this scope
    else printf("no\n");
                      ^