c++——文件的写入，读取

亦凉 2023-06-13 09:35 26阅读 0赞

写入文件：  
**流插入元素符：（<<）**  
cout<<\*\*\*\*\*<<endl;  
*输出信息到屏幕*

读取文件：  
**流提取运算符：（>>）**  
cin>>data;  
*从键盘输入信息*

#include "pch.h"
    #include<fstream>
    #include <iostream>
    
    using namespace std;
    
    int main() 
    { 
    	char data[100];
    
    	//以写模式打开文件
    	ofstream outfile;
    	outfile.open("d://test/test01.txt");
    
    	cout << "writing to the file..." << endl;
    	cout << "enter your name:";
    	cin.getline(data,100);//从外部读取一行
    
    	//向文件写入用户输入数据
    	outfile << data << endl;
    
    	cout << "enter your age:";
    	cin >> data;
    	cin.ignore();
    
    	//再次向文件写入用户输入数据
    	outfile << data << endl;
    
    	//关闭文件
    	outfile.close();
    
    	//以读模式打开文件
    	ifstream infile;
    	infile.open("d://test/test01.txt");
    
    	cout << "Reading from the file..." << endl;
    	infile >> data;
    
    	//在屏幕上写入数据
    	cout << data << endl;
    
    	//再次从文件读取数据
    	infile >> data;
    	cout << data << endl;
    
    	infile.close();
    
    	return 0;
    
    }

#include "pch.h"
    #include<fstream>
    #include <iostream>
    
    using namespace std;
    
    //向文件内部写入数据，并将数据读出
    void file_wr(void)
    { 
    	char data[100];
    
    	//以写模式打开文件
    	ofstream outfile;
    	outfile.open("d://test/test01.txt");
    
    	cout << "writing to the file..." << endl;
    	cout << "enter your name:";
    	cin.getline(data,100);//从外部读取一行
    
    	//向文件写入用户输入数据
    	outfile << data << endl;
    
    	cout << "enter your age:";
    	cin >> data;
    	cin.ignore();
    
    	//再次向文件写入用户输入数据
    	outfile << data << endl;
    
    	//关闭文件
    	outfile.close();
    
    	//以读模式打开文件
    	ifstream infile;
    	infile.open("d://test/test01.txt");
    
    	cout << "Reading from the file..." << endl;
    	infile >> data;
    
    	//在屏幕上写入数据
    	cout << data << endl;
    
    	//再次从文件读取数据
    	infile >> data;
    	cout << data << endl;
    
    	infile.close();
    }
    
    //将数据从一文件复制到另一文件中
    void file_copy() 
    { 
    	char data[100];
    	ifstream infile;
    	ofstream outfile;
    
    	infile.open("d://test/test01.txt");
    	outfile.open("d://test/test01_copy.txt");
    
    	cout << "copy from test01.txt to test01_copy.txt" << endl;
    	while (!infile.eof()) { 
    	
    		infile >> data;
    		cout << data << endl;
    		outfile << data << endl;
    	}
    
    	infile.close();
    	outfile.close();
    }
    
    //测试
    int main() 
    { 
    	file_wr();
    	file_copy();
    	return 0;
    }