为什么这个反向字符串函数会产生seg错误？

void reverse_str(char s[])  {
    int i,j;
    char ch;
    for(i = 0,j = strlen(s) - 1; i < j; i++,j--)  {
        ch = s[i];
        s[i] = s[j];
        s[j] = ch;
    }
    return ;
}

几乎可以肯定,因为i和j相互传递(无论它们是索引还是指针在这里都无关紧要).例如,任何具有偶数个字符的字符串都会出现此问题.

请考虑弦鼓的以下顺序：

0123 <- indexes
     ----
s = "drum",i = 0,j =  3,swap d and m.
s = "mrud",i = 1,j =  2,swap r and u.
s = "murd",i = 2,j =  1,swap u and r,oops,we've passed each other.
s = "mrud",i = 3,j =  0,swap m and d.
s = "drum",i = 4,j = -1,swap who kNows what,undefined behavIoUr.

请注意,对于具有奇数长度的字符串,您将不会遇到此问题,因为我最终等于j(在中间字符处).

i< j check也修复了这个问题,因为它检测到指针相等和指针相互传递.