如何在c#中循环计数？

Question

这是一个带有 setter 和 getter 概念的简单初学者程序 现在我必须先输入用户名和密码才能受到欢迎 如果我输入错误信息，它应该显示无效并且还剩 5 次尝试然后如果我再次输入错误信息，它应该显示 4 次尝试，依此类推，最后当所有尝试都结束时，它应该挂起程序或锁定屏幕左右

using System;


namespace ConsoleApplication4
{
    class Program
    {
        static void Main(string[] args)
        {
            demo obj = new demo();
            string uname, pass;
            Console.ForegroundColor = ConsoleColor.Green;
        label1:
            Console.Clear();
            Console.WriteLine("Enter username");
            uname = Console.ReadLine();
            Console.WriteLine("Enter Password");
            pass = Console.ReadLine();
            obj.setName(uname);
            obj.setPass(pass);
            if (obj.getName() == "niit")
            {
                if (obj.getPass() == "1234")
                {
                    Console.WriteLine("welcome");

                }
            }
            else
            {
                Console.Clear();
                Console.WriteLine("Invalid");
                Console.WriteLine("\n \n \n To try again enter y");
                int n = 5;
                string yes = Console.ReadLine();
                    if (yes == "y")
                {
                    while (n >= 1)
                    {
                        Console.Write(n + " Tries left");
                        goto label1;
                        n = --n;
                    }
                }
            }

            Console.ReadKey();

        }
    }
    class demo
    {
        private string name, pass;
        public void setName(string name)
        {
            this.name = name;
        }
        public string getName()
        {
            return name;
        }
        public void setPass(string pass)
        {
            this.pass = pass;
        }
        public string getPass()
        {
            return pass;
        }
    }
}

请建议一个简单的初学者代码来使循环工作并倒计时

Answer 1

一个while循环就足够了。使用布尔值检测成功的密码输入。 输入后，它将跳出循环。 无效尝试将减少 AttemptsLeft int。 注意：我没有在 Visual Studio 中尝试过，逻辑应该是合理的，但我建议调试并逐步测试它是否符合您的条件。

static void Main(string[] args)
    {
        demo obj = new demo();
        string uname, pass;
        Console.ForegroundColor = ConsoleColor.Green;
    label1:
        Console.Clear();
        Console.WriteLine("Enter username");
        uname = Console.ReadLine();
        Console.WriteLine("Enter Password");
       bool SuccessfulPassword = false;
       int AttemptsLeft = 5;
        while(!SuccessfulPassword && AttemptsLeft > 0){
        pass = Console.ReadLine();
        obj.setName(uname);
        obj.setPass(pass);
        if (obj.getName() == "niit")
        {
            if (obj.getPass() == "1234")
            {
                Console.WriteLine("welcome");
                SuccessfulPassword = true;
            }
        }
        else
        {
            AttemptsLeft--;
            Console.Clear();
            Console.WriteLine("Invalid");
            Console.WriteLine("\n \n \n To try again enter y");
            int n = 5;
            string yes = Console.ReadLine();
                if (yes == "y")
            {

                    Console.Write(AttemptsLeft + " Tries left");
            }
        }

        Console.ReadKey();
        }
    }

Answer 2

试试这个更新后的 main 方法：

static void Main(string[] args)
        {
            demo obj = new demo();
            int n = 5;
            string uname, pass;
            Console.ForegroundColor = ConsoleColor.Green;
            //Console.Clear();
        label1:
            Console.WriteLine("\n");
            Console.WriteLine("Enter username");
            uname = Console.ReadLine();
            Console.WriteLine("Enter Password");
            pass = Console.ReadLine();
            obj.setName(uname);
            obj.setPass(pass);
            if (obj.getName() == "niit" && obj.getPass() == "1234")
            {
                    Console.WriteLine("welcome");
            }
            else
            {
                //Console.Clear();
                if (n < 1)
                {
                    //Add ur screenlock n hang prog code 
                    Console.Clear();
                    Console.WriteLine("ScreenLock");
                }
                else
                {

                    Console.WriteLine("\n Invalid");
                    Console.WriteLine("\n To try again enter y");
                    string yes = Console.ReadLine();
                    Console.WriteLine("\n");
                    if (yes == "y")
                    {
                        while (n >= 1)
                        {
                            Console.Write(n + " Tries left");
                            n = --n;
                            goto label1;


                        }
                    }
                }
            }

            Console.ReadKey();

        }

Answer 3

namespace ConsoleApplication4
{
class Program
{
    static void Main(string[] args)
    {
        demo obj = new demo();
        string uname, pass;
        boolean successful = false;
        int32 tries = 5;
        Console.ForegroundColor = ConsoleColor.Green;
    label1:
        Do 
        {
        Console.Clear();
        Console.WriteLine("Enter username");
        uname = Console.ReadLine();
        Console.WriteLine("Enter Password");
        pass = Console.ReadLine();
        obj.setName(uname);
        obj.setPass(pass);
        if (obj.getName() == "niit")
        {
            if (obj.getPass() == "1234")
            {
                Console.WriteLine("welcome");
                successful = true;
            }
        }
        if (!successful)
        {
            tries--;
            Console.Clear();
            Console.WriteLine("Invalid");
            if (tries > 1)
            { 
               Console.WriteLine("Have " + tries + " attempts left");
            }
            ElseIf (tries == 1)
            {
               Console.WriteLine("Have only one more attempt left");
            }
            Else
            {
               Console.WriteLine("Maximum number of tries exceed");
               Console.WriteLine("Goodbye");
            }
        }
        } While(!successful && Tries > 0);
    }
}

Answer 4

每次输入错误时，都会重新计算int n = 5; 所以每次你还有 5 次尝试。

您可以做的是在static void Main(string args[]) 方法之外声明您的计数

就像：

int n =5;
static void Main(string args[])
{

}

Answer 5

您的问题是以下嵌套的if-contions

if (obj.getName() == "niit")
{
    if (obj.getPass() == "1234")
    {
        Console.WriteLine("welcome");
    }
}
else
{
\\...
}

如果用户名正确而pass不正确，则不会进入else分支。 一个更好的解决方案来要求输入直到它是有效的 id a do ... while 循环 下面的例子比你的有很多改进。

static void Main(string[] args)
{
    demo obj = new demo();
    string uname, pass;
    Console.ForegroundColor = ConsoleColor.Green;
    int maxTries;
    int tries = maxTries = 5;
    do
    {
        if (tries != maxTries)//second and more
        {
            Console.Clear();
            Console.WriteLine("Invalid");
            Console.Write("\n\t" + tries + " Tries left");
            Console.WriteLine("\n\n\n\tTry again? (y/n)");
            string input;
            do
            {
                input = Console.ReadLine();
            } while (input != "y" && input != "n");

            if (input == "n")
            {
                return; // exit the program
            }
        }

        Console.Clear();
        Console.WriteLine("Enter username");
        uname = Console.ReadLine();
        Console.WriteLine("Enter Password");
        pass = Console.ReadLine();
        obj.setName(uname);
        obj.setPass(pass);
        tries--;
    } while (obj.getName() != "niit" || obj.getPass() != "1234");
    Console.WriteLine("Wellcome");
}

PS：类应以大写字母开头。

goto 是旧时代的产物，它会弄乱你的程序结构并使事情变得比现在更复杂。我知道的唯一正确用途是用于切换开关，这也仅在极少数情况下需要。

虚构的应该是：

string vehicleType = "car";
switch(vehicleType)
{
    case "truck":
        Console.WriteLine("two wheeles and");
        goto case "car";
    case "car":
        Console.WriteLine("two wheeles and");
        goto case "motor cycle";
    case "motor cycle":
        Console.WriteLine("two wheeles");
        break;
    case "boat":
        Console.WriteLine("no wheeles");
        break;
}