c语言字典序全排列代码

以下是C语言的字典序全排列代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void swap(char *a, char *b) {
    char temp = *a;
    *a = *b;
    *b = temp;
}

void reverse(char *begin, char *end) {
    while (begin < end) {
        swap(begin, end);
        begin++;
        end--;
    }
}

int next_permutation(char *str, int len) {
    int i = len - 2;
    while (i >= 0 && str[i] >= str[i + 1]) {
        i--;
    }
    if (i < 0) {
        return 0;
    }
    int j = len - 1;
    while (j > i && str[j] <= str[i]) {
        j--;
    }
    swap(&str[i], &str[j]);
    reverse(&str[i + 1], &str[len - 1]);
    return 1;
}

int main() {
    char str[] = "abc";
    int len = strlen(str);
    do {
        printf("%s\n", str);
    } while (next_permutation(str, len));
    return 0;
}