Day 4 (item 1: household income and expenditure records)

 FamilyAccount.java And Utility.java Put it under the same root directory

// The code is as follows ：

package project01;
public class FamaillyAccount {
    public static void main(String[] arg){
        String details = " Income and expenditure \t Amount of account \t Amount of revenue and expenditure \t say      bright \n";
        int balance = 10000;
        boolean loopFlag = true;
        do {
            System.out.println("----------------- Family income and expenditure accounting software -----------------");
            System.out.println("                  1  Income and expenditure details                     ");
            System.out.println("                  2  Registered income                     ");
            System.out.println("                  3  Register expenses                     ");
            System.out.println("                  4  refund     Out                     ");
            System.out.println();
            System.out.println("                  Please select （1-4）:                  ");
            char keyNumber = Utility.readMenuSelection();
            switch (keyNumber){
                case '1':
                    System.out.println("----------------- Current revenue and expenditure details record -----------------");
                    System.out.println(details);
                    System.out.println("-----------------------------------------------");
                    break;
                case '2':
                    System.out.println(" The amount of income this time :");
                    int amount1 = Utility.readNumber();
                    System.out.println(" This income statement :");
                    String dec1 = Utility.readString();
                    System.out.println("------------------- Registration completed --------------------\n");
                    balance += amount1;
                    details += " income " + "\t" + balance + "\t\t" + amount1 + "\t\t" + dec1 +"\n";
                    break;
                case '3':
                    System.out.println(" The amount of this expenditure is :");
                    int amount2 = Utility.readNumber();
                    System.out.println(" This expenditure statement :");
                    String dec2 = Utility.readString();
                    balance -= amount2;
                    details += " spending " + "\t" + balance + "\t\t" + amount2 + "\t\t" + dec2 +"\n";
                    System.out.println("------------------- Registration completed --------------------\n");
                    break;
                case '4':
                    System.out.println(" Confirm whether to exit Y/N:");
                    char conf = Utility.readConfirmSelection();
                    break;
            }
        }while (loopFlag);
    }
}

stay FamilyAccount.java Used in Utility The document code is as follows ：

import java.util.Scanner;
/**
Utility Tool class ：
 Encapsulating different functions into methods , You can use its functions directly by calling methods , There is no need to consider the specific function implementation details .
*/
public class Utility {
    private static Scanner scanner = new Scanner(System.in);
    /**
	 For interface menu selection . This method reads the keyboard , If the user types ’1’-’4’ Any character in , Then the method returns . The return value is the character that the user typed .
	*/
	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(" Wrong choice , Please re-enter ：");
            } else break;
        }
        return c;
    }
	/**
	 Input for income and expense amounts . This method reads a number from the keyboard that does not exceed 4 An integer of bit length , And take it as the return value of the method .
	*/
    public static int readNumber() {
        int n;
        for (; ; ) {
            String str = readKeyBoard(4);
            try {
                n = Integer.parseInt(str);
                break;
            } catch (NumberFormatException e) {
                System.out.print(" Wrong number input , Please re-enter ：");
            }
        }
        return n;
    }
	/**
	 Input for income and expense statements . This method reads a number from the keyboard that does not exceed 8 Bit length string , And take it as the return value of the method .
	*/
    public static String readString() {
        String str = readKeyBoard(8);
        return str;
    }
	
	/**
	 Input to confirm selection . This method reads... From the keyboard ‘Y’ or ’N’, And take it as the return value of the method .
	*/
    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(" Wrong choice , Please re-enter ：");
            }
        }
        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(" Input length （ No more than " + limit + "） error , Please re-enter ：");
                continue;
            }
            break;
        }

        return line;
    }
}

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