【C语言及程序设计】项目2-15：模块化的简单银行系统设计

问题描述：

https://edu.csdn.net/course/play/456/4808

 

// 银行系统.cpp: 定义控制台应用程序的入口点。
//#include "stdafx.h"
#include <stdlib.h>
#pragma warning (disable: 4996)int  PassTest();
void ibalance();
void withdraw();
void deposit();
void PassChange();int main()
{int ichoice,testresult;printf("欢迎光临草泥马银行\n\n");testresult = PassTest();while (testresult){printf("\n您可办理下面的业务：\n");printf("   1.查询余额\n");printf("   2.取款\n");printf("   3.存款\n");printf("   4.改密码\n");printf("   0.退出\n");printf("请输入（0-4）：");scanf("%d", &ichoice);switch (ichoice){case 1:ibalance(); break; case 2:withdraw(); break;case 3:deposit(); break;case 4:PassChange(); break;default:break;}if (ichoice == 0){break;}}return 0;
}int PassTest()
{printf("请输入6位密码：");while (1){int pass, passstored, itry(1), righttime(0);FILE *fp;fp = fopen("D:\\code\\pass.dat", "r");if (fp == NULL){printf("File cannot open! ");exit(0);}for (int i = 0; i < 6; i++){scanf_s("%1d", &pass);fscanf(fp, "%1d", &passstored);if (pass == passstored){righttime++;}}if (righttime == 6){fclose(fp);return 1;break;}else if (itry<3){itry++;printf("密码错误累计%d次，请重新输入：", itry - 1);continue;}else{printf("密码错误累计%d次，系统终止\n", itry);fclose(fp);return 0;break;}}}void ibalance() 
{double balance;FILE *fp;fp = fopen("D:\\code\\balance.dat", "r");if (fp == NULL){printf("File cannot open! ");exit(0);}fscanf(fp, "%lf", &balance);printf("余额：%.2lf\n\n", balance);fclose(fp);}void withdraw() 
{double cash, balance, diff;printf("请输入取款额：");scanf("%lf", &cash);FILE *fp;fp = fopen("D:\\code\\balance.dat", "r");if (fp == NULL){printf("File cannot open! ");exit(0);}fscanf(fp, "%lf", &balance);if (balance>cash){diff = balance - cash;fclose(fp);fp = fopen("D:\\code\\balance.dat", "w");fprintf(fp, "%lf", diff);fclose(fp);fp = fopen("D:\\code\\balance.dat", "r");fscanf(fp, "%lf", &balance);printf("现余额：%.2lf\n\n", balance);fclose(fp);}else{printf("取款额大于余额，取款失败\n\n");fclose(fp);}}void deposit() 
{double cash, balance, diff;printf("请输入存款额：");scanf("%lf", &cash);FILE *fp;fp = fopen("D:\\code\\balance.dat", "r");if (fp == NULL){printf("File cannot open! ");exit(0);}fscanf(fp, "%lf", &balance);diff = balance + cash;fclose(fp);fp = fopen("D:\\code\\balance.dat", "w");if (fp == NULL){printf("File cannot open! ");exit(0);}fprintf(fp, "%lf", diff);fclose(fp);fp = fopen("D:\\code\\balance.dat", "r");if (fp == NULL){printf("File cannot open! ");exit(0);}fscanf(fp, "%lf", &balance);printf("现余额：%.2lf\n", balance);fclose(fp);}void PassChange()
{while (1){int pass, pass2;printf("请输入新密码：");scanf("%d", &pass);if (pass>=100000 && pass <=999999){printf("请再输入新密码：");scanf("%d", &pass2);if (pass == pass2){FILE *fp;fp = fopen("D:\\code\\pass.dat", "w");fprintf(fp, "%d", pass);fclose(fp);printf("密码修改成功\n");}break;}else{printf("密码位数不足，请输满6位\n");continue;}}}

　　

感想：

数据写入硬盘（如写入文本文档）似乎是在fclose之后才生效

比如取款后显示“现余额”，必须这么写

		fp = fopen("D:\\code\\balance.dat", "w");fprintf(fp, "%lf", diff);fclose(fp);fp = fopen("D:\\code\\balance.dat", "r");fscanf(fp, "%lf", &balance);printf("现余额：%.2lf\n\n", balance);fclose(fp);

　　

 

 

 

 

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