View Compilation Error

0_0_16000219_2647.cpp: In function 'int main()':
0_0_16000219_2647.cpp:6:14: error: 'scanf' was not declared in this scope
 scanf("%d",&n);
              ^
0_0_16000219_2647.cpp:7:10: error: 'getchar' was not declared in this scope
  getchar();
          ^
0_0_16000219_2647.cpp:11:11: error: 'gets' was not declared in this scope
     gets(a);
           ^
0_0_16000219_2647.cpp:18:24: error: 'printf' was not declared in this scope
     printf("%d\n",count);
                        ^