循环重复本身？ [英] Loop repeating itself?

问题描述

我目前正在尝试自学C，因为我认为这将是C ++和C＃的良好选择（以及在上课之前获得先机）。因此，我决定在此处编写此循环：

I am currently trying to teach myself C since I believe that will be a good segue into C++ and C# (as well as getting a headstart prior to the start of classes). So I have decided to write this loop here:

#include <stdio.h>

int main()
{
    bool continueLoop = true;
    char response;
    printf("ARE YOU READY TO RUMBLE?!?!\n Y/N\n");
    response = getchar();
    int counter = 0;

        do
        {
            counter++;
            if (response == 'Y')
            {
                printf("AWESOME!");
                continueLoop == false;
                return 0;
            }
            else if (response == 'N')
            {
                printf("YOU FAIL!");
                continueLoop == false;
                return 0;
            }
           if (continueLoop == true)
            {
                printf("I do not understand your input!\n");
                printf("Please reinput! Y/N\n");
                response = getchar();
            }
            if(counter == 5)
            {
                printf("Exiting!");
                continueLoop == false;
                goto exit;
            }
        }while (continueLoop == true);

    exit:
        return 0;
}

我的问题如下：为什么在什么时候如果我输入例如 M作为答案，它将自我循环两次；但是，如果给出适当的条件，则可以正确终止。

My question(s) is(are) as follows: Why is it when if I input for example 'M' as my answer, it will loop itself twice; however if it is given the proper condition then terminates correctly.

此外，我应该将响应转换为单个长度的数组，而不是 getchar（）比较它，或者应该通过printf语句来完成它，这样 printf（您准备朗读了吗？！？n％s，响应）；

Also, instead of getchar() should I instead convert response into a single length of array and then try to compare it somehow, or perhaps it should be done via the printf statement as so printf("ARE YOU READY TO RUMBLE?!? \n %s", response);

如果有帮助，我将C-Lion作为我的IDE，因为我拒绝在vi，emacs或记事本中编写任何代码。

If it helps, I am using C-Lion as my IDE as I refuse to write any code in vi, emacs, or notepad.

编辑代码

int main()
{


    char response;
    printf("ARE YOU READY TO RUMBLE?!?!\n Y/N\n");
    scanf(" %c", &response);

    int counter = 0;


    while (counter < 5)
    {
        counter++;
        if (response == 'Y')
        {
            printf("AWESOME!");

            return 0;
        }
        else if (response == 'N')
        {
            printf("YOU FAIL!");

            return 0;
        }
        else
        {
            printf("I do not understand your input!\n");
            printf("Please reinput! Y/N\n");
            response = getchar();
        }

    }


    return 0;


}

推荐答案

当您输入 M 时，您实际上并不是仅输入 M ；您输入的是 M ，然后输入换行符。因此， getchar（3）首次调用时将返回 M ，然后返回 \n 。因此循环执行两次。

When you input M, you're not really inputting M only; you are inputting M followed by a newline. So getchar(3) will return M when you first call it, and then it will return \n on the second call. Hence the loop executes twice.

您可以使用 scanf（％c捕获输入并忽略空格（换行符，制表符，空格等）。 ，& response）。注意格式字符串中的前导空格；必须强制 scanf（3）跳过空格。

You can capture input and ignore whitespaces (newlines, tabs, spaces, etc) with scanf(" %c", &response). Note the leading whitespace in the format string; it is required to force scanf(3) to skip blanks.

此外，前两个if中的这些语句是无用的：

Also these statements inside the first two if's are useless:

continueLoop == false;

您将 continueLoop 与<$ c $进行比较c> false ，然后丢弃结果（如果您未使用 -Wall 进行编译，则应该这样做，因为这很可能会给您一个警告）。

You compare continueLoop to false and then throw the result away (if you're not compiling with -Wall, you should because this will very likely give you a warning).

您可能想要分配而不是比较：

You probably want assignment instead of comparison:

continueLoop = false;

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