参考网址:

(128条消息) C++ 深究fstream打开方式ios::app,ios::ate,ios::in,ios::out_悟名堂的博客-CSDN博客_fstream ios::app

例程

默认(覆盖原文件)

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
#include<fstream>
#include<iostream>
using namespace std;
int main()
{
	char data[100];
	
	//第一次打开文件
	ofstream outfile;
	outfile.open("D:\\afile.dat");
	cout << "Writing to the file" << endl;
	cout << "Enter your name:";
	cin.getline(data, 100);
	outfile << data << endl;
	outfile.close();
	
	//第二次打开文件
	ofstream outfile2;
	outfile2.open("D:\\afile.dat");//**待修改语句**
	cout << "Enter your age:";
	cin >> data;
	outfile2 << data << endl;
	outfile2.close();//第二次关闭文件
	
	return 0;
}

使用iso::app(在文末尾添加)

1
outfile2.open("D:\\afile.dat", ios::app);