TQC+ JAVA

JPA04.java

import java.util.Scanner;
public class JPA03 {
    static Scanner keyboard = new Scanner(System.in);
    public static void main(String[] args) {
		int sum = 0;
		boolean check = false;
		System.out.print("Input a string of numbers: ");
		String str = keyboard.nextLine();
		try {
			Integer.parseInt(str);
		} catch(Exception e) {
			check = true;
		}
		if(!check) {
			System.out.println("尾端遞迴：" + sumR(str, sum));
			System.out.println("迴圈：" + sumLoop(str));
		} else {
			System.out.println("尾端遞迴：" + sum);
			System.out.println("迴圈：" + sum);
		}
		System.out.print("Input a string of numbers: ");
		str = keyboard.nextLine();
		try {
			Integer.parseInt(str);
		} catch(Exception e) {
			check = true;
		}
		if(!check) {
			System.out.println("尾端遞迴：" + sumR(str, sum));
			System.out.println("迴圈：" + sumLoop(str));
		} else {
			System.out.println("尾端遞迴：" + sum);
			System.out.println("迴圈：" + sum);
		}
	}
	public static int sumR(String str, int sum) {
		if(str.equals("")) {
			return sum;
		}
		return sumR(str.substring(1), sum + Integer.parseInt(str.substring(0, 1)));
	}
	public static int sumLoop(String str) {
		int sum = 0;
		for(int index=0;index<str.length();index++) {
			sum += Integer.parseInt(String.valueOf(str.charAt(index)));
		}
		return sum;
	}
}