clearv.c

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#include "stdio.h"
#include "shead.h"
void ClearVote()
{
    char DataFile[10]="houshuan";
    candidate *s,*t,TempS;
    int total=CANDIDATENUM,i;
    int recNumber=0;
    FILE * fp;

    /* 分配内存空间存从文件中读出的信息 */
    s=(candidate*)malloc(total*sizeof(candidate));
    if(s==NULL)
    {
     printf("malloc memory error!\n");
     printf("press any key to end program");
     fflush(stdin);
     getch();
     exit(0);
    }
    clrscr();
    fp=fopen(DataFile,"rb");
    if(fp==NULL)
    {
        printf("Clear Vote Error");
        printf("\nPress any key to continu...\n");
        free(s);
        getch();
        return;
    }
    while(fread(&s[recNumber],sizeof(candidate),1,fp)!=(int)NULL)
    {
        s[recNumber].votenum=0;/* 清空投票信息 */
        recNumber++;
        if(recNumber>=total)
        {
         total+=INCREASE;/* 增加存储空间 */
         t=(candidate*)realloc(s,total*sizeof(candidate));
         if(t==NULL)
         {
          free(s);
          printf("rellot memory fail");
          fflush(stdin);
          getch();
          exit(0);
         }
         s=t;
         t=NULL;
        }
    }
    fclose(fp);
    fp=fopen(DataFile,"wb+");
    if(fp==NULL)
    {
        printf("Clear Vote Error");
        printf("\nPress any key to continu...\n");
        free(s);
        getch();
        return;
    }
    for(i=0;i<recNumber;i++)
    {
     if(fwrite(&s[i],sizeof(candidate),1,fp)!=1)
     {
      printf("write file %s fail\n",DataFile);
      perror("write file fail");
      fflush(stdin);
      getch();
      exit(0);
     }
    }
    fclose(fp);
    fp=fopen(DataFile,"rb");
    printf("Clear vote success!!\n\nNumber\tName\t\tvote\n");
    while(fread(&TempS,sizeof(candidate),1,fp)!=(int)NULL)
    {
     printf("%ld\t%-8s\t\t%d\n",TempS.Number,TempS.Name,TempS.votenum);
    }
    fclose(fp);
    fflush(stdin);
    printf("Press any key to continue...");
    getch();

}