c#简单评分系统

Question

我正在制作一个简单的游戏。当玩家的答案正确时，我试图给他 +1 分，但它一直说相同的分数 1。我希望在你的答案正确时不断更新分数。

因此，如果您有两个答案是正确的，则分数应该更新为 2，但事实并非如此，而是一直显示 1...

        start:

        Random numbergenerator = new Random ();

        int num1 = numbergenerator.Next(1,11);
        int num2 = numbergenerator.Next(1,11);
        int score = 0; // THIS IS THE SCORE

        Console.WriteLine("Whats " + num1 + " times " + num2 + "?");

        var answer = Convert.ToInt32(Console.ReadLine());

        if ( answer == num1 * num2) {
            Console.ForegroundColor = ConsoleColor.Green;
            Console.WriteLine("Thats the correct answer!");
            Console.ResetColor();
            ++score; // Gives score
            Console.WriteLine("Your score: " + score);
        } else {
            Console.ForegroundColor = ConsoleColor.Red;
            Console.WriteLine("Bummer, try again!");
            Console.ResetColor();
            ++score; // Gives score
            Console.WriteLine("Your score: " + score);
        }
        goto start;
    }
}

Answer 1

1) 来自 C# 规范 ( MSDN )

Furthermore, a variable initializer in a local variable declaration corresponds exactly to an assignment statement that is inserted immediately after the declaration.

换句话说，每次您的程序进入start 赋值语句时，score 都会初始化为0

我建议在 start 之前移动初始化(最好也移动 numbergenerator initialization。):

    Random numbergenerator = new Random ();
    int score = 0; // THIS IS THE SCORE

    start:

    int num1 = numbergenerator.Next(1,11);
    int num2 = numbergenerator.Next(1,11);

    Console.WriteLine("Whats " + num1 + " times " + num2 + "?");

    var answer = Convert.ToInt32(Console.ReadLine());

    if ( answer == num1 * num2) {
        Console.ForegroundColor = ConsoleColor.Green;
        Console.WriteLine("Thats the correct answer!");
        Console.ResetColor();
        ++score; // Gives score
        Console.WriteLine("Your score: " + score);
    } else {
        Console.ForegroundColor = ConsoleColor.Red;
        Console.WriteLine("Bummer, try again!");
        Console.ResetColor();
        ++score; // Gives score
        Console.WriteLine("Your score: " + score);
    }
    goto start;

2) 不要使用goto。因为

• 它使代码困惑
• 降低可读性

这个article关于 GO TO 对你来说可能很有趣。

我建议更换从 while (true){ 开始goto start; 使用 它应该看起来像这样:

    Random numbergenerator = new Random ();
    int score = 0; // THIS IS THE SCORE

    while(true)
    {
        int num1 = numbergenerator.Next(1,11);
        int num2 = numbergenerator.Next(1,11);

        Console.WriteLine("Whats " + num1 + " times " + num2 + "?");

        var answer = Convert.ToInt32(Console.ReadLine());

        if ( answer == num1 * num2) {
            Console.ForegroundColor = ConsoleColor.Green;
            Console.WriteLine("Thats the correct answer!");
            Console.ResetColor();
            ++score; // Gives score
            Console.WriteLine("Your score: " + score);
        } else {
            Console.ForegroundColor = ConsoleColor.Red;
            Console.WriteLine("Bummer, try again!");
            Console.ResetColor();
            ++score; // Gives score
            Console.WriteLine("Your score: " + score);
        }
    }

3)提取方法，不是关键，但我建议通过提取方法来提高可读性。此方法将包含循环体。代码应如下所示:

public void TryToGuessMultiplication_GameStep(int num1, int num2)
{
            Console.WriteLine("Whats " + num1 + " times " + num2 + "?");

            var answer = Convert.ToInt32(Console.ReadLine());

            if ( answer == num1 * num2) {
                Console.ForegroundColor = ConsoleColor.Green;
                Console.WriteLine("Thats the correct answer!");
                Console.ResetColor();
                ++score; // Gives score
                Console.WriteLine("Your score: " + score);
            } else {
                Console.ForegroundColor = ConsoleColor.Red;
                Console.WriteLine("Bummer, try again!");
                Console.ResetColor();
                ++score; // Gives score
                Console.WriteLine("Your score: " + score);
            }
}

...

Random numbergenerator = new Random ();
int score = 0; // THIS IS THE SCORE

while(true)
{
    int num1 = numbergenerator.Next(1,11);
    int num2 = numbergenerator.Next(1,11);
    TryToGuessMultiplication_GameStep(int num1, int num2);      
}

4) 你的代码包含 bug 如果你只想在答案正确时增加分数，你应该从 else block 中删除++score。

5) 不要复制代码 如您所见，if block 和else block 中的最后两个语句是相同的。我建议将它们从 if else 运算符中移出:

public void TryToGuessMultiplication_GameStep(int num1, int num2)
{
            Console.WriteLine("Whats " + num1 + " times " + num2 + "?");

            var answer = Convert.ToInt32(Console.ReadLine());

            if ( answer == num1 * num2) {
                Console.ForegroundColor = ConsoleColor.Green;
                Console.WriteLine("Thats the correct answer!");
                ++score; // Gives score
            } else {
                Console.ForegroundColor = ConsoleColor.Red;
                Console.WriteLine("Bummer, try again!");
            }
            Console.ResetColor();
            Console.WriteLine("Your score: " + score);
}

这还不是全部。现在你可以看到了

            Console.ForegroundColor = ConsoleColor.Green;
            Console.WriteLine("Thats the correct answer!");

与

非常相似(但不一样!!!)

            Console.ForegroundColor = ConsoleColor.Red;
            Console.WriteLine("Bummer, try again!");

而且我们无法通过将它们移出 if else 运算符来改进我们的代码。但是有一个技巧 - 我们可以提取方法，借助它我们将减少代码行数:

public void PrintUserMessage(ConsoleColor color, string message)
{
        Console.ForegroundColor = color;
        Console.WriteLine(message);
}

public void TryToGuessMultiplication_GameStep(int num1, int num2)
{
            Console.WriteLine("Whats " + num1 + " times " + num2 + "?");

            var answer = Convert.ToInt32(Console.ReadLine());

            if ( answer == num1 * num2){
                PrintUserMessage( ConsoleColor.Green, "Thats the correct answer!");
                ++score; // Gives score
            }else
                PrintUserMessage( ConsoleColor.Red,"Bummer, try again!");

            Console.ResetColor();
            Console.WriteLine("Your score: " + score);
}