苹果终端上按Ctrl-D输出d字符 [英] CTRL-D on Mac terminal outputs a D character

问题描述

我运行这个例子（从Kernighan和Ritchie的C语言书第1.5.2节），在Mac OS X计算机终端上：

I am running this example (from Kernighan and Ritchie's C book section 1.5.2) on a mac OS X machine terminal:

#include <stdio.h>

int main()
{
    int c, nl;

    nl = 0;
    while((c = getchar()) != EOF)
        if(c == '\n')
            ++nl;

    printf("%d\n", nl);
}

我运行应用程序，并立即 CTRL-D 进入EOF字符。该项目输出 0D 并终止。 0是预期的输出，但哪里额外的'D'从何而来？

I run the app and enter the EOF character CTRL-D immediately. The program outputs 0D and terminates. The 0 is the expected output, but where does the extra 'D' come from?

我看到这个线程并的这个常见问题，但找不到答案。

I saw this thread and this faq, but could not find an answer.

推荐答案

我敢打赌，终端呈现出 ^ D （正常插入符号符号）和离开的光标插入符号，那么你的程序是印刷 0 \\ n ，因为 NL 0覆盖插入符。

I bet the terminal is showing a ^D (normal caret notation) and leaving the cursor on the caret, then your program is printing 0\n because nl is 0 overwriting the caret.

添加睡眠（5）前的最后的printf 要证实这一点。

Adding a sleep(5) before the final printf should confirm this.

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