文件的修改
我的文件小程序，我截取了其中一部分，我不明白的是为什么我调用modify后，原来a中输入的数据格式就不对了呢？请高手指点一开始创建的 产品名称 品牌 产品型号 进价 库存数量
bijiben lenovle g450 5000 50
bijibne lenovle k450 5000 10
biji lian v450 5000 20
调用modify后 ，对第一行的库存数量进行修改：
产品名称 品牌 产品型号 进价 库存数量
bijiben lenovle g450 5000 60
bijibne lenovle k450 5000 10
biji lian v450 5000 20
# include<stdio.h>
# include<stdlib.h>
# include<string.h>
struct computer // 产品信息结构体
{
char name[20];
char company[20];
char xinghao[20];
int inprice;
int number;
}one;
FILE *fp;
void creat0()//创建产品信息文件头
{
if((fp=fopen("a","w+"))==NULL)
{printf("不能建立该文件\n");exit(0);}
fprintf(fp,"%20s%20s%20s%20s%20s\n","产品名称","品牌","产品型号","进价","库存数量");//输入表头
fclose(fp);
}
void creat() //1.创建产品信息文件
{
char c='y';
if((fp=fopen("a","a+"))==NULL) //创建产品文件a并打开
{
printf("\n不能建立文件");
exit(0);
}
printf("请输入数据,产品名称,品牌,产品型号,进价,库存数量\n");
while(c=='y'||c=='Y') //判断是否继续输入
{
scanf("%s%s%s%d%d",one.name,,one.xinghao,&one.inprice,&one.number);
fprintf(fp,"%20s%20s%20s%20d%20d\n",one.name,,one.xinghao,one.inprice,one.number);//将数据输入文件a
printf("继续输入请按y，退出请按n\n");
getchar();
c=getchar();
}
fclose(fp);//关闭文件a
}
void modify() //4.修改笔记本产品信息文件
{
int k=0,m;
char namel[20],xinghaol[20],c1='y',c2;
long offset;
while(c1=='y'||c1=='Y') //判断是否继续修改数据
{
if((fp=fopen("a","r+"))==NULL)//打开文件a
{
printf("无法打开文件\n");exit(0);
}
printf("请输入要修改的产品的名称和型号\n");
scanf("%s%s",namel,xinghaol);
fscanf(fp,"%s%s%s%s%s\n",&one.name,&,&one.xinghao,&one.name,&one.name);//从文件读出表头汉字
do //查找要修改的一行
{
offset=ftell(fp);
{if(offset==-1L)
printf("error\n");}
fscanf(fp,"%s%s%s%d%d\n",&one.name,&,&one.xinghao,&one.inprice,&one.number);
if((!strcmp(xinghaol,one.xinghao))&&(!strcmp(namel,one.name)))
{
k=1;
break;
}
}while((!feof(fp)));
if(k)
{
printf("已查到记录为\n");
printf("%20s%20s%20s%20d%20d\n",one.name,,one.xinghao,one.inprice,one.number);//输出要修改的信息
printf("确实要修改请按y，否则请按n\n ");
getchar();
c2=getchar();
if(c2=='y'||c2=='Y')//判断是否修改
{fseek(fp,offset,SEEK_SET); //把指针指到要修改的选项
printf("请选择要修改的选项\n");
printf("1.产品名称 2.品牌或厂商\n");
printf("3.产品型号 4 进价 \n");
printf("5.库存数量 \n");
printf("请输入要修改的选项\n");
scanf("%d",&m);
printf("请输入要修改的数据\n");
fseek(fp,offset,SEEK_SET);
switch(m)
{
case 1: printf("请输入产品名称\n");
scanf("%s",one.name);
fprintf(fp,"%20s%20s%20s%20d%20d\n",one.name, ,one.xinghao,one.inprice ,one.number);
break;
case 2: printf("请输入品牌\n");
scanf("%s",);
fprintf(fp,"%20s%20s%20s%20d%20d\n",one.name, ,one.xinghao,one.inprice ,one.number);
break;
case 3: printf("请输入产品型号\n");
scanf("%s",one.xinghao);
fprintf(fp,"%20s%20s%20s%20d%20d\n",one.name, ,one.xinghao,one.inprice ,one.number);
break;
case 4: printf("请输入进价\n");
scanf("%d",&one.inprice);
fprintf(fp,"%20s%20s%20s%20d%20d\n",one.name, ,one.xinghao,one.inprice ,one.number);
break;
case 5: printf("请输入产品数量\n");
scanf("%d",&one.number);
fprintf(fp,"%20s%20s%20s%20d%20d\n",one.name, ,one.xinghao,one.inprice ,one.number);
break;
default :printf("error\n");
}
}
}
else printf("\n输错误，无此产品。\n");
printf("继续修改数据请按y，退出请按n \n");
fclose(fp);//关闭文件a
getchar();
c1=getchar();
}
}
void main()
{
creat0();
creat();
modify();
}
[ 本帖最后由 易哓天 于 2010-9-27 19:47 编辑 ]
