View Compilation Error

0_0_16055623_11191.cpp: In function 'int main()':
0_0_16055623_11191.cpp:6:10: error: 'getchar' was not declared in this scope
  getchar();
          ^
0_0_16055623_11191.cpp:7:21: error: 'scanf' was not declared in this scope
  while(scanf("%d",&n)!=EOF)
                     ^
0_0_16055623_11191.cpp:7:24: error: 'EOF' was not declared in this scope
  while(scanf("%d",&n)!=EOF)
                        ^
0_0_16055623_11191.cpp:11:12: error: 'gets' was not declared in this scope
    gets(str);
            ^
0_0_16055623_11191.cpp:16:24: error: 'printf' was not declared in this scope
   printf("%d\n",count/2);
                        ^