public class Test{

    public static void main(String[] args){

        int i    =    1;

        while(i<30){

            System.out.println(i);

            i++;

        }

    }

}

public class Test{

    public static void main(String[] args){

        int i    =    1;

        do{

            System.out.println(i);

            i++;

        }

        while(i<30);

        //do-while循环，先执行一次，然后在判断，如果条件成立，在循环执行，如果不成立，继续往下执行

    }

}

import java.util.*;

public class Test{

    public static void main(String[] args){

        Scanner    in    =    new Scanner(System.in);

        Random    ra    =    new Random();

        int r    =    ra.nextInt(10);

        int j;

        System.out.println("=======猜数字游戏=======");

        do{

            System.out.println("请输入要猜数字（0-9）：");

            int num    =    in.nextInt();

            if(num<r){

                System.out.println("小了");

                j    =    1;

            }

            else if(num>r){

                System.out.println("大了");

                j    =    2;

            }

            else{

                System.out.println("猜对");

                j    =    11;

            }

        }

        while(j!=11);

    }

}

public class Test{

    public static void main(String[] args){

        for(int i=1;i<30;i++){

            System.out.println(i);

        }

    }

}