这是什么，而（* P2 ++ = * P1 ++）;意思？ [英] What does while (*p2++ = *p1++); mean?

问题描述

我有一个code座：

int main ()
{
    char *p1 = "Hello";
    char *p2;
    p2 = (char*)malloc (20);
    memset (p2, 0, 20);
    while (*p2++ = *p1++);
    printf ("%s\n", p2);
}

但我无法解释该行的工作
而（* P2 ++ = * P1 ++）;
你可以让我知道这个操作公式中的顺序？

But I can not explain the working of the line while (*p2++ = *p1++); Could you let me know the order of operation in this formula?

推荐答案

这是经典的C code试图把一切在一行看起来非常聪明。

It's classic C code trying to look extremely clever by putting everything in one line.

而（* P2 ++ = * P1 ++）; 等同于

strcpy(p2, p1);
p1 += strlen(p1) + 1;
p2 += strlen(p2) + 1;

在换句话说，它拷贝一个空值终止字符串， P1 结束了指向源字符串的结束和 P2 指向目标字符串的结尾。

In other words, it copies a null-terminated string, with p1 ending up pointing to the end of the source string and p2 pointing to the end of the destination string.

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