輸入任意字符串 輸出這個字符串從小到大的排序

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


char *strings;
int count;
void bubble(char *strings,int count)
{
    register int m, n;
    register char s;
    for (m = 1; m<count; m++)
    for (n = count - 1; n >= m; --n)
    {
        if (strings[n - 1]>strings[n])
        {
            s = strings[n - 1];
            strings[n - 1] = strings[n];
            strings[n] = s;
        }
    }
}

int main()
{
    int count;
    char str[200];
    printf("請輸入字符串：\n");
    gets(str);
    count = strlen(str);
    bubble(str, count);
    printf("排序之后的字符串是：\n");
    printf("%s.\n", str);
    getchar();
    return 0;
}