关于setbuf()缓存的设置 fgets()读入一行字符串

/*输入：2
  12345
  abcde
  希望输出：
  0:12345
  1:abcde
*/
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
int main( void )
{
        char **instr, **p;
        int i, j;
 
        printf( "num: " );
        scanf( "%d", &j );//不能有"\n"
        if( !j )
             return 0;
//fflush( stdin );       // 论坛上讲用fflush()  或 setbuf()都能达到同样的结果,但我用fflush()没有实现.
setbuf(stdin,NULL);
        instr = (char **)malloc( sizeof(char *) * j );
        if( !instr )
               return 1;
        memset( instr, 0, sizeof(char *) * j );
        for( i = 0, p = instr; i < j; i++ )
        {
               printf( "i=%d:", i );
               *p = (char *)malloc( sizeof(char) * 80 );
               if( !*p )
                      return 1;
              fgets( *p,80,stdin );//从标准输入读入一行字符串,包括回车换行符"\n"
                (*p)[strlen(*p)-1] = '\0';
                *p++;
        }
 
        for( i = 0, p = instr; i < j; i++ )
        {
                printf( "%d: %s\n", i, *p );
                free( *p++ );
        }
        free( instr );
        return 0;
}