程序密码

Question

我已经制作了一个应用程序来解决一些使用矩阵的计算，我想对用户进行身份验证，以便在程序启动时授予他们访问权限。

我会告诉你我已经做过的事情。

int main() 
{

const string USERNAME = "claudiu";
const string PASSWORD = "123456";
string usr, pass;

cout << "Enter Username : ";
cin >> usr;

if(usr.length() < 4)
{
    cout << "Username length must be atleast 4 characters long.";
}
else 
{
    cout << "Enter Password : ";
    cin >> pass;
    if(pass.length() < 6)
    {
        cout << "Password length must be atleast 6 characters long";

    }
    else 
    {
        if(usr == USERNAME && pass == PASSWORD)
        {
            cout << "\n\nSuccessfully granted access" << endl;
        }
        else
        {
            cout << "Invalid login details" << endl;

        }
    }
}

这就是我的代码的样子。我想要做的就是当我输入错误的用户名或错误的密码时，程序会显示我写的信息然后让我介绍另一个用户名和密码，当我正确地介绍它们时，程序就会启动。

Answer 1

我会创建一个logged_in变量，然后在条件通过时将其设置为true并在while循环中运行整个登录过程：

#include <iostream>
#include <string>

using namespace std;

int main()
{

    const string USERNAME = "claudiu";
    const string PASSWORD = "123456";
    string usr, pass;
    bool logged_in = false;
    while (!logged_in)
    {
        cout << "Enter Username : ";
        cin >> usr;

        if (usr.length() < 4)
        {
            cout << "Username length must be atleast 4 characters long.";
        }
        else
        {
            cout << "Enter Password : ";
            cin >> pass;
            if (pass.length() < 6)
            {
                cout << "Password length must be atleast 6 characters long";

            }
            else
            {
                if (usr == USERNAME && pass == PASSWORD)
                {
                    cout << "\n\nSuccessfully granted access" << endl;
                    logged_in = true;
                }
                else
                {
                    cout << "Invalid login details" << endl;

                }
            }
        }
    }
    cout << "Passed login!\n";
}