文件

#include<stdio.h>
#include<stdlib.h>
struct goods_info
{
 int num;
 char name[12];
 int count;
 float price;
};
void save(struct goods_info *p);
void inGoodsInf(struct goods_info *p);
void read(void);

main()
{
 FILE *fp;
 char ch,flag=1;
 struct goods_info goods;
 if((fp=fopen("goods.dat","a+b"))==NULL)
 {
  printf("对不起，不能打开这个文件!/n");
  exit(-1);
 }
 fclose(fp);
 while(flag)
 {
  system("cls");
  printf("/n/n");
  printf("/t/t=============商品信息系统=============/n/n");
  printf("/t/t/t1.商品信息录入/n");
  printf("/t/t/t2.商品信息读取/n");
  printf("/t/t/t3.退出/n/n");
  printf("请输入功能号：");
  scanf("%d",&ch);printf("/n");
  switch(ch)
  {
  case 1:
   do
   {
    inGoodsInf(&goods);
    save(&goods);
    printf("是否继续输入(y/n)?");
    fflush(stdin);
    ch=getchar();
   }while(ch=='y'||ch=='Y');
   break;
  case 2:
   read();
   break;
  case 3:
   flag=0;
   break;
  default:
   printf("输入错误!!/n");
  }
 }
 system("cls");
 return 0;
}
void inGoodsInf(struct goods_info *p)
{
 system("cls");
 printf("/n/t==============商品信息录入=============/n/n");
 printf("请输入商品编号：");
 scanf("%d",&p->num);
 printf("请输入商品名称：");
 scanf("%s",&p->name);
 printf("请输入商品数量：");
 scanf("%d",&p->count);
 printf("请输入商品单价：");
 scanf("%f",&p->price);
}
void save(struct goods_info *p)
{
 FILE *fp;
 if((fp=fopen("goods.dat","rb++"))==NULL)
  printf("对不起，不能打开这个文件!/n");
 else
 {
  fseek(fp,0,SEEK_END);
  fwrite(p,sizeof(struct goods_info),1,fp);
  fclose(fp);
 }
}
void read()
{
 FILE *fp;
 struct goods_info goods;

 if((fp=fopen("goods.dat","rb"))==NULL)
 {
  printf("对不起，不能打开这个文件!/n");
  return;
 }
 system("cls");
 printf("/n/t/t============商品信息============/n/n");
 printf("商品编号/t商品名称/t商品数量/t商品单价/n");
 while(!feof(fp))
 {
  fread(&goods,sizeof(struct goods_info),1,fp);
  if(feof(fp))continue;
  printf("%d/t/t%s/t/t%d/t/t%.2f/n",goods.num,goods.name,goods.count,goods.price);
 }
 printf("/n请按回车键返回主菜单...");
 getchar();
 getchar();
 fclose(fp);
}