C/C++语法、库的使用

#include 
#include 

using namespace std;

int main()
{
	ifstream fin("in.txt");
	char c;
	fin>>c;
	cout<
#include 
using namespace std;

int main()
{
	freopen("in.txt","r",stdin);
	char c;
	cin>>c;
	cout<
#include 
using namespace std;

int main()
{
	FILE * fin;
	fin=fopen("in.txt","rb");
	//fin=stdin;
	char c;
	fscanf(fin,"%c",&c);
	cout<