第一步先分析需求
需要什么变量
int balance = 10000;
String details = "收支 \t账户金额 \t收支金额 \t说 明"+"\n";
boolean loopFlag = true;
先写框架用循环实现选择框
打印
然后从键盘输入选择项
退出要有相应的机制保护
package com.xatu.edu;
public class shouzhi {
public static void main(String[] args) {
// 声明余额变量,10000
// 声明记账本 初始化表头
// 声明布尔变量作为循环条件
// 再循环中
// 1打印主菜单
// 2获取用户的键盘输入
int balance = 10000;
String details = "收支 \t账户金额 \t收支金额 \t说 明"+"\n";
boolean loopFlag = true;
while (loopFlag) {
System.out.println("-----------------家庭收支记账软件-----------------");
System.out.println(" 1 收支明细 ");
System.out.println(" 2 登记收入 ");
System.out.println("3 登记支出");
System.out.println("4 退 出");
System.out.println(" 请选择(1-4):");
char userInput = Utility.readMenuSelection();
switch (userInput) {
case '1':
System.out.println(details);
break;
case '2':
System.out.println("输入金额");
int money = Utility.readNumber();
System.out.println("输入金额说明");
String info = Utility.readString();
balance=balance+money;
String str ="收入\t"+balance+"\t"+money+"\t"+info+"\n";
details +=str;
break;
case '3':
break;
case '4':
System.out.println("退出出马,");
char confirm = Utility.readConfirmSelection();
if(confirm=='Y') {
loopFlag = false;}
break;
default:
break;
}
}
}
}
package com.xatu.edu;
import java.util.*;
public class Utility {
private static Scanner scanner = new Scanner(System.in);
public static char readMenuSelection() {
char c;
for (; ; ) {
String str = readKeyBoard(1);
c = str.charAt(0);
if (c != '1' && c != '2' && c != '3' && c != '4') {
System.out.print("选择错误,请重新输入:");
} else break;
}
return c;
}
public static int readNumber() {
int n;
for (; ; ) {
String str = readKeyBoard(4);
try {
n = Integer.parseInt(str);
break;
} catch (NumberFormatException e) {
System.out.print("数字输入错误,请重新输入:");
}
}
return n;
}
public static String readString() {
String str = readKeyBoard(8);
return str;
}
public static char readConfirmSelection() {
char c;
for (; ; ) {
String str = readKeyBoard(1).toUpperCase();
c = str.charAt(0);
if (c == 'Y' || c == 'N') {
break;
} else {
System.out.print("选择错误,请重新输入:");
}
}
return c;
}
private static String readKeyBoard(int limit) {
String line = "";
while (scanner.hasNext()) {
line = scanner.nextLine();
if (line.length() < 1 || line.length() > limit) {
System.out.print("输入长度(不大于" + limit + ")错误,请重新输入:");
continue;
}
break;
}
return line;
}
}