编写程序：由键盘输入三个整数分别存入变量num1、num2、num3，
对它们进行排序（使用 if-else if-else），并且从小到大输出。

方法一

import java.util.Scanner;

class IfTest3{
	public static void main(String[] args){

		Scanner scan = new Scanner(System.in);

		System.out.println("请输入第一个整数：");
		int num1 = scan.nextInt();
		System.out.println("请输入第二个整数：");
		int num2 = scan.nextInt();
		System.out.println("请输入第三个整数：");
		int num3 = scan.nextInt();
		if(num1 < num2 && num1 < num3){
			if(num2 < num3){
				System.out.println("排序后的数为：" + num1 + " " + num2 + " " + num3);
			}else{
				System.out.println("排序后的数为：" + num1 + " " + num3 + " " + num2);
			}
		}else if(num2 < num1 && num2 < num3){
			if(num1 < num3){
				System.out.println("排序后的数为：" + num2 + " " + num1 + " " + num3);
			}else{
				System.out.println("排序后的数为：" + num2 + " " + num3 + " " + num1);
			}
		}else if(num3 < num1 && num3 < num2){
			if(num1 < num2){
				System.out.println("排序后的数为：" + num3 + " " + num1 + " " + num2);
			}else{
				System.out.println("排序后的数为：" + num3 + " " + num2 + " " + num1);
			}
		}
	}
}

方法二

import java.util.Scanner;

class IfTest2{
	public static void main(String[] args){

		Scanner scan = new Scanner(System.in);

		System.out.println("请输入第一个整数：");
		int num1 = scan.nextInt();
		System.out.println("请输入第二个整数：");
		int num2 = scan.nextInt();
		System.out.println("请输入第三个整数：");
		int num3 = scan.nextInt();

		if(num1 >= num2){
			if(num3 >= num1){
				System.out.println(num2 + "," + num1 + "," + num3);
			}else if(num3 <= num2){
				System.out.println(num3 + "," + num2 + "," + num1);
			}else{
				System.out.println(num2 + "," + num3 + "," + num1);
			}
		}else{
			if(num3 >= num2){
				System.out.println(num1 + "," + num2 + "," + num3);
			}else if(num3 <= num1){
				System.out.println(num3 + "," + num1 + "," + num2);
			}else{
				System.out.println(num1 + "," + num3 + "," + num2);
			}
		}
	}
}