modps.c

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#ifndef MODPASSWORD
#define MODPASSWORD
#include "stdio.h"
#include "user.h"
#include "conio.h"
  ModifyMyPassword(user m_user)
{
  char DataFile[10]="yonghu";
  FILE * fp=NULL;
  int err=0,recNumber=0,i=0;
  char ps[8],next='n';
  user *s,*t;
  int total=SIZE;/*SIZE 在user.h中定义为100*/
  clrscr();
  printf("Name:%s\n",m_user.Name);
  do  /*输入密码*/
  {
    printf("Old password(6):");
    scanf("%s",ps);     /* 输入旧密码 */
    ps[7]='\0';
    if(strcmp(ps,m_user.ps)!=0)   /* 输入的旧密码是否正确 */
    {
     printf("\nOld password Error!\nAgin(y/n):");
     fflush(stdin);
     err=1;  /* 标志位 */
     next=getchar();/*  是否继续 */
    }
    else
    {
     err=0;
    }
  }while((next=='y'||next=='Y')&&err==1);
  if(err==1) /* 如果输入错误，退出 */
    return;

 err=0;
 do  /*输入新密码*/
 {
  printf("input  new password(6characters):");
  scanf("%s",m_user.ps);
  m_user.ps[7]='\0';

  printf("input password agin(6characters):");
  scanf("%s",ps);
  ps[7]='\0';

  if(strcmp(ps,m_user.ps)!=0)   /* 两次输入的密码不一致 */
    {
     printf("\nTwice password is not same! \nAgin(y/n):");
     fflush(stdin);
     err=1;  /* 标志位 */
     next=getchar();/*  是否继续 */
    }
    else
    {
     err=0;
    }
  }while((next=='Y'||next=='y')&&err==1);

  if(err==1)
  {
   return;
  }

  fp=fopen(DataFile,"rb");
  if(fp==NULL)
  {
   printf("Open file %s fail!",DataFile);
   perror("Open file fail");
   printf("Press any key to return!");
   getch();
   return;
  }
  s=(user*)malloc(SIZE*sizeof(user));
  /*读取数据到数组*/
  while(fread(&s[recNumber],sizeof(user),1,fp)!=(int)NULL)
  {
   if(strcmp(s[recNumber].Name,m_user.Name)==0) /*修改对应的PS*/
   {
    strcpy(s[recNumber].ps,m_user.ps);
   }
   recNumber++;
   if(recNumber>=total)
   {
    total+=INCREAMENT;
    t=(user*)realloc(s,total*sizeof(user));
    if(t==NULL)
    {
     printf("alloc memory fail!\n");
     printf("press any key to continu...");
     free(s);/*释放内存*/
     getch();
     return;
    }
    s=t;
    t=NULL;
   }
  }
  fclose(fp);/*关闭文件*/
  /*将写入后的数据写回文件*/
  fp=fopen(DataFile,"wb");
  for(i=0;i<recNumber;i++)
  {
   if(fwrite(&s[i],sizeof(user),1,fp)!=1)
   {
    printf("\nwrite file %s fail!\n",DataFile);
    perror("Write file fail\n");
    printf("press any key to return...");
    free(s);/*释放内存*/
    getch();
    return;
   }
  }
  fclose(fp);
  printf("Password modify success!\n");
  printf("Press any key to continu...");
  getch();
  free(s);/*释放内存*/
}
#endif