View Compilation Error

0_0_35794460_15911.cpp: In function 'int main()':
0_0_35794460_15911.cpp:6:24: error: 'scanf' was not declared in this scope
     while(scanf("%d",&n) != EOF)
                        ^
0_0_35794460_15911.cpp:6:29: error: 'EOF' was not declared in this scope
     while(scanf("%d",&n) != EOF)
                             ^
0_0_35794460_15911.cpp:8:17: error: 'getchar' was not declared in this scope
         getchar();
                 ^
0_0_35794460_15911.cpp:16:34: error: 'printf' was not declared in this scope
             printf("%d\n",count/2);
                                  ^