关于从小到大输出问题

#include<stdio.h>
#include <string.h>

struct student
{
char num[20];
char name[20];

};
void main()
{
    struct student stu[10]={
    {"201060010","Shen"},
    {"201060002","Qian"},
    {"201060009","Jiang"},
    {"201060003","Sun"},
    {"201060005","Wang"},
    {"201060006","Zhou"},
    {"201060004","Li"},
    {"201060008","Zhen"},
    {"201060007","Wu"},
    {"201060001","Zhao"}
    };
    char a[10][300],temp[300];
    int i,j;
    for(i=0;i<10;i++)
        printf("%s      %s\n",stu[i].num,stu[i].name);
    for(i=0;i<10;i++)
        for(j=i+1;j<10;j++)
        {
            if(strcmp(stu[i].num,stu[j].num)>0)
            {
                strcpy(temp,stu[i].num);
                strcpy(stu[i].num,stu[j].num);
                strcpy(stu[j].num,temp);
            }
         }
   printf("====================================================\n");
     printf("Results:\n\n");
    for(i=0;i<10;i++)
    {
        printf("%s      \n",stu[i].num);
        
    }

}