1. C++从文件读写数据

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

int main()
{
    ifstream fcin("C:/Users/QDjyf/Desktop/ProgramLearning/1.in");
    ofstream fcout("C:/Users/QDjyf/Desktop/ProgramLearning/1.out");
    int a;
    
    fcin>>a;
    cout<<a<<endl;
    fcout<<a;
    return 0;
}