无法在C ++中使用附加模式在文件中插入数据

Question

my code is this:

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

int main()
{
fstream file;
file.open("abc.txt",ios::app);
file<<"hello";
file.close();
return 0;
}

The above code is creating an empty file.

Please can anyone point it out where i'm going wrong.

Answer 1

When you open your file, in addition to specifying append ( ios::app ), you must also specify that you want to output to the file ( ios::out ). You combine them with a bitwise or ( | ) since they represent single bit flags.

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

int main()
{
    fstream file;
    file.open("abc.txt",ios::app | ios::out);
    file << "hello";
    file.close();
    return 0;
}