deluser.c

学生成绩管理系统的开发

/*  deluser.c 删除用户信息                  */
#include "stdio.h"
void DelUser()
 {
    int i,j,k;
    long delnum;
    user TmpS;
    user s[SIZE];/*SIZE，在user.h头文件中定义的常量，值为100  */
    int recNumber;
    char DataFile[40] = "yonghu",next;
    FILE *fp;/*====fp指针指向存储数据的文件名====*/
begin:

    fp=fopen(DataFile,"rb");
    if (fp == NULL)
    {
        printf("\nOpen file %s fail!End with any key\n",DataFile);
        perror("Open file fail");
        getch();
        exit(1);
    }
    printf("please input the user'seatnum which you will delete:");
    scanf("%ld",&delnum);
    printf("the user you will delete is:%ld\n",delnum);
   recNumber=0;
    while((fread(&TmpS,sizeof(user),1,fp)) != (int)NULL)
    {
        if(TmpS.Number!=delnum)
            {
            s[recNumber].Number = TmpS.Number;
            strcpy(s[recNumber].Name, TmpS.Name);
            strcpy(s[recNumber].ps,TmpS.ps);
            s[recNumber].power = TmpS.power;
            recNumber++;
            }
    }
    printf("end shuzu while");
    fclose(fp);
    /*====将删除后的结构体记录写入文件====*/
        fp=fopen(DataFile,"wb+");
        if (fp == NULL)
        {
            printf("\nSet up file %sfail !end with anykey.\n",DataFile);
            perror("Set up fail");
            getch();
            exit(1);
        }
       for(i=0; i<recNumber; i++)
        {
            if(fwrite(&s[i],sizeof(user),1,fp)!=1)
            {
                printf("\nWrite file %s fail!end with anykey.\n",DataFile);
                perror("Write file fail!");
                    getch();
                    exit(1);
            }
        }
        fclose(fp);
     /*====显示删除后的文件====*/
    fp=fopen(DataFile,"rb");
    if (fp == NULL)
    {
        printf("\nOpen file%sfail!End with any key \n",DataFile);
        perror("Open file fail");
        getch();
        exit(1);
    }
    printf("the file after delete is:\n");
    printf("\nNumber \t\tName\tps\tpower\n");
    while(fread(&TmpS,sizeof(user),1,fp) != (int)NULL)
    {
        if(TmpS.Number!=0)
        printf("\n%ld\t        %s\t   %s\t  %d\n",TmpS.Number,TmpS.Name,TmpS.ps,TmpS.power);
    }
    fclose(fp);

    printf("\nGo on ?(y/n)");
    next=getche();
    putchar('\n');
    if ( next =='y' || next =='Y') goto begin;
 }