给一个由n个单词组成的字符串排序

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

#define MAX_N 100
#define MAX_LEN 20

int sortWords(char *s)
{
if (s == NULL) return 0;

char tmp[MAX_N][MAX_LEN];
int cnt = 0;
for (int i = 0; i < strlen(s); i++)
{
int j = i;
while (j < strlen(s))
{
if (s[j] == ' ') break;
j++;
}

strncpy(tmp[cnt], &s[i], j - i);
tmp[cnt][j - i] = 0;
cnt++;
i = j;
}

qsort(tmp, cnt, sizeof(tmp[0]), (int (*)(const void*,const void*))strcmp);

s[0] = 0;
for (int i = 0; i < cnt; i++)
{
strcat(s, tmp[i]);
if (i != cnt - 1) strcat(s, " ");
}

printf("result:%s\n", s);
}

int main()
{
char s[MAX_N * MAX_LEN];
gets(s);
sortWords(s);

return 0;
}