求助一道题

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

struct score
{
    int num;
    char name[20];
    float results1;
    float results2;
    float results3;
    float sum;
}list[20];

int main()
{
    FILE *fp;
    char str[100],temp[5][20];
    int i=0,flag,num;
    if((fp=fopen("score.txt","r"))==NULL)
        printf("打开文件出错");
    while(1)
    {
        if(fgets(str,100,fp)==NULL)
        {
            printf("读取文件出错");
            break;
        }
        sscanf(str,"%s\t%s\t%s\t%s\t%s\t%s",temp[0],list[i].name,temp[1],temp[2],temp[3],temp[4]);
        list[i].num=atoi(temp[0]);
        list[i].results1=atof(temp[1]);
        list[i].results2=atof(temp[2]);
        list[i].results3=atof(temp[3]);
        list[i].sum=atof(temp[4]);
        //printf("num=%d,name=%s,results1=%f,results2=%f,results3=%f,sum=%f\n",list[i].num,list[i].name,list[i].results1,list[i].results2,list[i].results3,list[i].sum);
        i++;
    }
    num=i;
    printf("请选择查询类型：(0.学号查询,1.姓名查询)");
    scanf("%d",&flag);
    if(flag==0)
    {
        printf("请输入所查学号：");
        scanf("%d",&flag);
        for(i=0;i<num;i++)
        {
            if(flag==list[i].num)
                break;
        }
        if(i<num)
            printf("该学生信息为：num=%d,name=%s,results1=%f,results2=%f,results3=%f,sum=%f\n",list[i].num,list[i].name,list[i].results1,list[i].results2,list[i].results3,list[i].sum);
        else
            printf("无此学生信息！\n");
    }
    else
    {
        printf("请输入所查学生姓名：");
        scanf("%s",str);
        for(i=0;i<num;i++)
        {
            if(memcmp(str,list[i].name,strlen(list[i].name))==0)
                break;
        }
        if(i<num)
            printf("该学生信息为：num=%d,name=%s,results1=%f,results2=%f,results3=%f,sum=%f\n",list[i].num,list[i].name,list[i].results1,list[i].results2,list[i].results3,list[i].sum);
        else
            printf("无此学生信息！\n");
    }

    system("pause");
    return 0;
}