C++输入输出流（读取，写入，复制文件）

//读取文件内容
#include<string>
#include<iostream>
#include<fstream>
using namespace std;

int main()
{
	char c;
	fstream file;
	file.open("test.txt",ios::in);
	
		while (!file.fail())
		{		
			if (file.get(c))
			{
				cout << c;
			}		
		}
	
	file.close();
}

//写入文件
#include<string>
#include<iostream>
#include<fstream>
using namespace std;

int main()
{
	cout << "Creat a file" << endl;
	ofstream file;
	file.open("test.txt",fstream::app);
	if (!file.fail())
	{
		file << "你好" << endl;
		file << "还好" << endl;
		
		
		file.close();
	}

}
}

//C++实现文件复制

#include<string>
#include<iostream>
#include<fstream>
using namespace std;

int main()
{
	char c;
	int sum=0;
	fstream infile,outfile;
	infile.open("test.txt",ios::in);		//打开目标文件
	outfile.open("Demo.txt",ios::out);		//创建文件别名（复制）
	if (!infile.fail())					//检查文件打开是否成功
	{
		cout << "开始写入文件........" << endl;	
		while (infile.get(c))		//从打开的文件中写入字符
		{
			outfile << c;
			sum++;
		}

	
	}
	cout << "总计输入字符：" <<sum<< endl;
	
	infile.close();
	outfile.close();

	cout << "文件写入复制完毕........" << endl;
}

}