我有这个项目,一个使用c中文件和结构的ATM帐户系统。 现在,除了存款/提款功能外,几乎所有功能都关闭了。 如果我没记错的话,您只需要读取文件并调用要在算术运算中使用的变量,然后将其写回到文件中即可进行更新。
如果用户为该变量输入一个新值(但我没有那个cuz,则用户可以随意更改其帐户余额),效果很好。
但是当我这样做时,它是行不通的。
简而言之,我的问题是我的交易(用户输入要存入的金额,系统将该金额添加到保存在二进制文件中的用户帐户余额中,然后系统会为新帐户余额,然后覆盖旧的帐户余额)特别不起作用,我的结构和用户输入变量未加
这是我的功能
void deposit()
{
system("cls");
FILE *fp,*fp1;
struct acc rec,rec1;
int id,pinc,found=0,count=0;
float dv=0,wv=0;
fp=fopen(fname,"rb");
fp1=fopen("tempacc.dat","wb");
printf("\nEnter Account No :");
scanf("%d",&id);
printf("\nEnter PIN :");
scanf("%d",&pinc);
while(1)
{
fread(&rec,sizeof(rec),1,fp);
if(feof(fp))
{
break;
}
if(rec.no==id && rec.pin==pinc)
{
found=1;
printf("current balance:%0.2f",&rec.id);
printf("\nEnter initial deposit:");
scanf("%d",&rec.id);
printf("\nEnter Deposit value:");
scanf("%f",dv);
rec.id = rec.id + dv; <--- (this part doesn't work)
printf("\nNew Account Balance:%f",rec.id);
fwrite(&rec,sizeof(rec),1,fp1);
}
else
{
fwrite(&rec,sizeof(rec),1,fp1);
}
}
fclose(fp);
fclose(fp1);
if(found==0)
{
printf("Sorry No Record Found\n\n");
}
else
{
fp=fopen(fname,"wb");
fp1=fopen("tempacc.dat","rb");
while(1)
{
fread(&rec,sizeof(rec),1,fp1);
if(feof(fp1))
{
break;
}
fwrite(&rec,sizeof(rec),1,fp);
}
}
fclose(fp);
fclose(fp1);
}
我的主要人
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
struct acc
{
int no;
char name[100];
int pin;
float id;
};
void append();
void display();
void displayAll();
void modify();
void search();
void deposit();
char mygetch();
char fname[]={"accdb.dat"};
int main()
{
char ch;
while(1)
{
system("cls"); //clrscr();
printf("==================Welcome to Banking System=============\n\n");
printf("A. Open an Account \n\n");
printf("B. Bank transaction \n\n");
printf("C. Exit\n\n");
//printf("D. Display\n\n");
//printf("E. Display All\n\n");
//printf("F. Search\n\n");
printf("========================================================\n\n");
printf("\nPlease enter your Choice:");
scanf("%c",&ch);
switch(ch)
{
case 'A': append();
break;
case 'B': modify();
break;
case 'C': exit(0);
case 'D': display();
break;
case 'E': displayAll();
break;
case 'F': search();
break;
}
mygetch();
}
return 0;
}
void append()
{
system("cls");
FILE *fp;
struct acc rec;
fp=fopen(fname,"ab");
printf("\nEnter Account no:");
scanf("%d",&rec.no);
getchar();
printf("\nEnter Account name:");
scanf("%[^\n]s",rec.name);
printf("\nEnter PIN:");
scanf("%d",&rec.pin);
printf("\nEnter Initial Deposit:");
scanf("%f",&rec.id);
fwrite(&rec,sizeof(rec),1,fp);
fclose(fp);
}
void display()
{
system("cls");
FILE *fp;
struct acc rec;
int id,found=0;
fp=fopen(fname,"rb");
printf("\nEnter the account number:");
scanf("%d",&id);
while(1)
{
fread(&rec,sizeof(rec),1,fp);
if(feof(fp))
{
break;
}
if(rec.no==id)
{
found=1;
printf("\n========================================================\n\n");
printf("\t\t Account Details of %d\n\n",rec.no);
printf("========================================================\n\n");
printf("Name\tBalance\n\n");
printf("%s\t",rec.name);
printf("%0.2f\t\n\n",rec.id);
printf("========================================================\n\n");
}
}
if(found==0)
{
printf("\nSorry No Record Found");
}
fclose(fp);
}
void deposit()
{
system("cls");
FILE *fp,*fp1;
struct acc rec,rec1;
int id,pinc,found=0,count=0;
float dv=0,wv=0;
fp=fopen(fname,"rb");
fp1=fopen("tempacc.dat","wb");
printf("\nEnter Account No :");
scanf("%d",&id);
printf("\nEnter PIN :");
scanf("%d",&pinc);
while(1)
{
fread(&rec,sizeof(rec),1,fp);
if(feof(fp))
{
break;
}
if(rec.no==id && rec.pin==pinc)
{
found=1;
printf("current balance:%0.2f",&rec.id);
printf("\nEnter initial deposit:");
scanf("%d",&rec.id);
printf("\nEnter Deposit value:");
scanf("%f",dv);
rec.id = rec.id + dv;
//scanf("%f",&rec.id);
printf("\nNew Account Balance:%f",rec.id);
//scanf("%f",&rec.id);
fwrite(&rec,sizeof(rec),1,fp1);
//fflush(stdin);
}
else
{
fwrite(&rec,sizeof(rec),1,fp1);
}
}
fclose(fp);
fclose(fp1);
if(found==0)
{
printf("Sorry No Record Found\n\n");
}
else
{
fp=fopen(fname,"wb");
fp1=fopen("tempacc.dat","rb");
while(1)
{
fread(&rec,sizeof(rec),1,fp1);
if(feof(fp1))
{
break;
}
fwrite(&rec,sizeof(rec),1,fp);
}
}
fclose(fp);
fclose(fp1);
}
void search()
{
FILE *fp;
struct acc rec;
int found=0;
char name[20];
fp=fopen(fname,"rb");
printf("\nEnter the Account Name:");
scanf("%s",&name);
while(1)
{
fread(&rec,sizeof(rec),1,fp);
if(feof(fp))
{
break;
}
if(strcmp(name,rec.name)==0)
{
printf("\n========================================================\n\n");
printf("\t\t Account Details of %d\n\n",rec.no);
printf("========================================================\n\n");
printf("Name\tbalance\n\n");
printf("%s\t",rec.name);
printf("%0.2f\t\n\n",rec.id);
printf("========================================================\n\n");
}
}
if(found==0)
{
printf("\nSorry No Record Found");
}
fclose(fp);
}
void displayAll()
{
system("cls");
FILE *fp;
struct acc rec;
fp=fopen(fname,"rb");
printf("\n========================================================\n\n");
printf("\t\t All Account Details\n\n");
printf("========================================================\n\n");
printf("ID\tName\tPIN\tBalance\n\n");
while(1)
{
fread(&rec,sizeof(rec),1,fp);
if(feof(fp))
{
break;
}
printf("%d\t",rec.no);
printf("%s\t",rec.name);
printf("%d\t",rec.pin);
printf("%0.2f\t\n\n",rec.id);
}
printf("========================================================\n\n");
fclose(fp);
}
char mygetch()
{
char val;
char rel;
scanf("%c",&val);
scanf("%c",&rel);
return (val);
}
void modify()
{
system("cls");
FILE *fp,*fp1;
struct acc rec,rec1;
int id,pinc,found=0,count=0;
fp=fopen(fname,"rb");
fp1=fopen("tempacc.dat","wb");
printf("\nEnter Account No:");
scanf("%d",&id);
printf("\nEnter PIN:");
scanf("%d",&pinc);
while(1)
{
fread(&rec,sizeof(rec),1,fp);
if(feof(fp))
{
break;
}
if(rec.no==id && rec.pin==pinc)
{
found=1;
int sch;
printf("\tWelcome to Banking System\n");
printf("1.Balance Inquiry\n");
printf("2.Deposit\n");
printf("3.Withdrawal\n");
printf("4.quit\n");
scanf("%d",&sch);
switch (sch)
{
case 1:
display();
break;
case 2:
fclose(fp);
deposit();
break;
case 3:
//withdrawal();
break;
case 4:
printf("Thank you for your patronage\n");
exit(0);
break;
}
}
}
}
答案 0 :(得分:0)
由于缺少更多细节,我会猜测,您的scanf
组合实际上是在读%d%f
,即十进制数紧随浮点数。如果是这样,它应该以某种方式起作用:如果您输入123.456
,则应该先存入初始存款123
,再注入新的存款0.456
。
但是我想您是想让用户输入两个不同的数字,并在两个数字之间输入。如果是这样,您的输入将是第一个数字,然后是换行符,然后是第二个数字。您需要将其解析为%d %f
(因为空格匹配任意数量的空格,包括换行符)。如果您不希望第一个scanf
等到第一个数字之后的第一个非空格,建议您在第二个scanf
中包含空格,即进行扫描" %f"
。
如果所有这些都是错误的,则scanf
仍然可能出了点问题,因此您应该对此进行错误检查。阅读手册,查看有效输入应返回的内容,如果不是得到的内容,则让您的代码抱怨。