利用qsort() 对字符串的内容快速排序

#include "stdafx.h"

/* QSORT.C: This program reads the command-line

* parameters and uses qsort to sort them. It

* then displays the sorted arguments.

*/

#include <stdlib.h>

#include <string.h>

#include <stdio.h>

int compare( const void *arg1, const void *arg2 );

void main( int argc, char **argv )

{

char a[255]="1723649\0";

int k=strlen(a);

qsort((void *)a,(size_t)strlen(a),sizeof(char),compare);

printf ("%s",a);

}

int compare( const void *arg1, const void *arg2 )

{

return -(((char *)arg1)[0]-((char*)arg2)[0]);//降序，这个值取负则为升序

}