字符串数组进行排序

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define Nmax  10
#define Mmax  20

char buf[Mmax];
int M = 0;
int compare(void *i, void *j) {
	return strcmp( *(char **)i, *(char **)j );
}
main() {
	
	int i, N;
	char* a[Nmax];

	for ( N = 0; N < Nmax; N++ ) {
		a[N] = &buf[M];
  	    printf("N=%d\n", N);
		if ( scanf("%s", a[N]) == EOF ) {
			printf("%d\n", N);
			break;
		}
		M += strlen( a[N] )+1;
	}
 	
 	qsort( a, N, sizeof(char*), compare);

	for ( i = 0; i < N; i++ ) {
		printf("%s\n", a[i] );
	}
	system("pause");
}