我有这个项目，一个使用c中的文件和结构的ATM帐户系统。现在除了我的存款/取款功能外，几乎所有功能都有所下降。如果我没弄错的话，你只需要读取文件并调用想要在算术运算中使用的变量，然后将其写回文件进行更新。
如果用户为所述变量输入一个新值，它可以正常工作（但我没有那个因为用户可以随意更改他/她的帐户余额）。
但是，当我这样做时，它不起作用。
简而言之，我的问题是我的交易（用户输入存款金额，系统将该金额添加到保存在二进制文件中的用户账户余额，然后系统获得这两个金额的总和，然后新的账户余额覆盖旧帐户余额）具体不起作用，我的结构和用户输入变量没有加起来
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
#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;
}
}
}
}
缺乏更多的细节，我猜你的scanf组合实际上是为%d%f读取，即一个十进制数后面紧跟一个浮点数。如果是这种情况，它应该在某种程度上起作用：如果你输入123.456，它应该采取初始存款123和新存款0.456。
但我想你的意思是让用户输入两个不同的数字，在它们之间输入。如果是，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）。如果你不希望第一个scanf等到第一个数字之后的第一个非空格，我建议你用第二个scanf包括空格，即扫描" %f"。
如果所有这些都是错误的，那么你的scanf可能还有问题所以你应该对此进行错误检查。阅读手册，看看它应该返回什么有效输入，然后让你的代码抱怨，如果这不是它得到的。