C语言读取字符串，并对字符串排序

#include<stdio.h>
#include<string.h>
#define SIZE 81    //每行的字符长度限制
#define LIM 20     //最多读取行数
#define HALT " "   //用空字符串终止输入
void stsrt(char *strings[],int num);//字符串指针排序函数

int main (void){
char input[LIM][SIZE];
char *ptstr[LIM];
int ct =0;
int k;

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");
//输入字符串
while(ct < LIM && gets(input[ct] )!= NULL && input[ct][0] !='\0')
{
ptstr[ct] =input[ct];
ct++;
}
stsrt(ptstr , ct );//调用排序函数

puts ("\n here's the sorted list :\n");

//打印输出排序之后的指针字符串

for (k=0;k <ct ;k++)
{
puts(ptstr[k]);
}

//打印输出排序之后的数组字符串
puts ("\n here's the list :\n");

for (k=0;k <ct ;k++)
{
puts(input[k]);
}

return 0;
}

//字符串指针排序函数
void stsrt(char *strings[],int num){
char *temp;
int top ,seek;
//对字符串指针进行排序
for (top=0; top< num-1;top++ )
for (seek = top+1;seek<num;seek++)
//对字符串进行比较strcmp
if(strcmp(strings[top] ,strings[seek] ) > 0)
//交换排序
{
temp = strings[top];
strings[top] = strings[seek];
strings[seek]= temp;
}
}