11.6 字符串示例：字符串排序

字符串排序只要是用strcmp()函数来确定两个字符串的顺序，一般的做法是读取字符串函数，排序字符串并打印出来。
输入示例

o that i was where i would be,then would i be where i am not,but where i am i must be,and where i would be i can not.

输出示例

and where i would be i can not.but where i am i must be,o that i was where i would be,then would i be where i am not,

程序示例

#include<stdio.h>#include<string.h>#define SIZE 81#define LIM 20       /*可读入的最多行数*/#define HALT ""     /*空格字符串停止输入*/void stsrt(char *strings[], int num);char *s_gets(char *st, int n);int main(){    char input[LIM][SIZE]; /*存储输入的数组*/    char *ptstr[LIM];      /*内含指针变量的数组，均指向每一行的首地址*/    int ct = 0;            /*输入计数*/    int k;                 /*输出计数*/    printf("input up to %d lines,and i will sort them.\n", LIM);    printf("to stop,press the enter key at a line's start.\n");/*此处只需要直接指向字符数组某一行的首地址，便可以实现怼字符串的输入*/    while (ct < LIM&&s_gets(input[ct], SIZE) != NULL&&input[ct][0] != '\0')    {        ptstr[ct] = input[ct]; /*设置指针指向字符串*/        ct++;    }    stsrt(ptstr, ct);    puts("\nhere's the sorted list:\n");    for (k = 0; k < ct; k++)        puts(ptstr[k]);       /*排序后的指针*/    return 0;}/*选择排序*//*字符串-指针-排序函数&&指针与一维数组*/void stsrt(char *strings[], int num){    char *temp;    int top, seek;    for(top=0;top<num-1;top++)        for(seek=top+1;seek<num;seek++)            if (strcmp(strings[top], strings[seek]) > 0)            {                temp = strings[top];                strings[top] = strings[seek];                strings[seek] = temp;            }}char *s_gets(char *st, int n) /*指针与一维数组*/{    char *ret_val;    int i = 0;    ret_val = fgets(st, n, stdin);    if (ret_val)    {        while (st[i] != '\n'&&st[i] != '0')            i++;        if (st[i] == '\n')    st[i] = '\0';        else            while (getchar() != '\n')                continue;    }    return ret_val;}

关于strcmp()函数：
strcmp()函数比较所有的字符，不只是字母，如果 第一个字符串位于第二个字符串的前面，strcmp()就返回正数，反之则返回负数。