如何从 getch() 区分两个具有相似响应的击键 [英] How can I distinguish two keystrokes which have similar responses from getch()

问题描述

正如我在标题中所说，如何区分两个与 getch() 响应相似的击键.在这个代码块中，K 和左箭头键的 getch() 响应是相同的，所以当我输入大写 k case 75 时.我该如何解决?我也遇到了其他一些词的问题.

As I said in title, How can I distinguish two keystrokes which have similar responses from getch(). In this code block, K's and left arrow key's getch() responses are same, so when I type capital k case 75 works. How can I fix it? Also I got this problem with some other words.

     while(1){
            ch1=getch();
        switch( ch2 = getch())
       {
if(ch1 != 0xE0)
{
             default:
            for(i=' ';i<'}';i++)
            {
                if(i == ch2)
                {
                /*SOME STUFF*/
                printf("%c" , iter->x);
                }
 break;
            }


            else
            {
                case 72: printf("UP WAS PRESSED\n");
            break;
           /*Some other stuff*/
            }
        }
    }

推荐答案

当按下左箭头等特殊字符时，getch 将首先返回值 0 或 0xE0，然后它会返回一个键码(与 ASCII 码不同).

When a special character such as left-arrow is pressed, getch will first return either the value 0 or 0xE0, then it will return a key code (which is not the same as an ASCII code).

来自 MSDN:

_getch 和 _getwch 函数从控制台而不回显字符.这些功能都不能用于阅读CTRL+C.读取功能键或箭头键时，每个函数必须被调用两次；第一次调用返回 0 或 0xE0，并且第二个调用返回实际的键码.

The _getch and _getwch functions read a single character from the console without echoing the character. None of these functions can be used to read CTRL+C. When reading a function key or an arrow key, each function must be called twice; the first call returns 0 or 0xE0, and the second call returns the actual key code.

因此您需要检查 0 或 0xE0 是否告诉您下一个字符是键码，而不是 ASCII 码.

So you need to check for a 0 or 0xE0 which tells you the next character is a key code, not an ASCII code.

键码列表:https://msdn.microsoft.com/en-us/library/windows/desktop/dd375731(v=vs.85).aspx

你的 if(ch1 != 0xE0) 不在任何 case 之外，所以它会被跳过.此外，当您进入循环时，您总是会调用 getch 两次.因此，如果您没有获得关键代码，您最终会阅读 2 个常规字符，并且很可能会跳过其中一个.

Your if(ch1 != 0xE0) is outside of any case, so it gets skipped over. Also, you're always calling getch twice when you enter the loop. So if you didn't get a key code, you end up reading 2 regular characters and most likely skip one of them.

使用单个 getch 开始循环.然后检查 0 或 0xE0，如果找到则再次调用 getch.

Start you loop with a single getch. Then check for 0 or 0xE0, and if found then call getch again.

while (1) {
    int ch = getch();
    int keycode = 0;

    if (ch == 0 || ch == 0xe0) {
        keycode = 1;
        ch = getch();
    }
    switch (ch) {
    ...

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