i was trying to create login and registration syste. The registration work perfectly well until i stop the app and run it again so that i can login(it delete everything in the file). How can I make my file save even when I run again my app bellow is attached my code

#include <iostream>
#include <fstream>
using namespace std;
double amount;
int main () {
ifstream fin;
ofstream fout;
fin.open("admin.txt");
fout.open("userDB.txt");

int number;
string username,password, adminUsername, adminPassword,newusername,newpassword; 
fin>>adminUsername;
fin>>adminPassword;

if(number == 1){
cout<<"Welcome to the Normal User Login Page : \n\n";
cout<<"Enter Username : ";
cin>>username;
cout<<"Enter password : ";
cin>>password;  
}
else if(number == 2) {
cout<<"Welcome to the Registration and Deposit Page\n";
cout<<"Enter administrator username and password.\n";
cout<<"Enter username : ";
cin>>username;
cout<<endl;
cout<<"Enter Password : ";
cin>>password;
if(username == adminUsername){
    if(password == adminPassword){
        cout<<"Welcome admin \n";
        cout<<"1. Deposit money for client\n";
        cout<<"2. Register new client\n";
        cout<<"3. Reset your password \n\n";
        cout<<"Enter option to proceed : ";
        cin>>number;
        if(number==2){
            cout<<"Client register form\n";
            cout<<"Enter client username : ";
            cin>>newusername;
            cout<<"Enter client password : ";
            cin>>newpassword;
            cout<<"initial deposit : ";
            cin>>amount;
            fout<<newusername<<endl;
            fout<<newpassword<<endl;
            fout<<amount<<endl;
            
        }
        
    }
    else{
        cout<<"Wrong password";
    }   
}
else{
    cout<<"Wrong UserName";
}
    
}
fin.close();
fout.close();
return 0;
}

I am new to C kindly help.

CodePudding user response：

It is because whenever the output file is opened it clears the contents of it. You need to specify the option to append to the file in order to prevent that:

fout.open("userDB.txt",std::ios_base::app);