The difference between the three loops (for, while, do...while)

The difference between the three loops

//第一个区别
public class HelloWorld {
    
    
    public static void main(String[] args){
    
    
        //for循环
        for(int i = 3; i<3; i++){
    
    
            System.out.println("HelloWorld");//3<3不成立 无法输出HelloWorld
        }
        //while循环
        int j = 3;
        while (j<3){
    
    
            System.out.println("HelloWorld");//3<3不成立 无法输出HelloWorld
            j++;
        }
        //do...while循环
        int k = 3;
        do{
    
    
            System.out.println("HelloWorld");//3<3虽然不成立，但语句会先执行输出一个HelloWorld之后再进行比较
            k++;
        }while(k<3);
    }
}

//第二个区别（for循环和while循环）
public class HelloWorld {
    
    
    public static void main(String[] args){
    
    
        for(int i = 1; i<3; i++){
    
    
            System.out.println("HelloWorld");
        }
        System.out.println("-------");
        //System.out.println(i); for中的i为局部变量，而while中的j为全局变量
        int j = 1;
        while (j<3){
    
    
            System.out.println("HelloWorld");
            j++;
        }
        System.out.println(j);
    }
}

	//三种循环的死循环
public class HelloWorld {
    
    
    public static void main(String[] args){
    
    
        //for的死循环
       /* for (;;){
            System.out.println("for");//在for中“;;”表示恒为true
        }*/
//while的死循环
      /*  while(true){
            System.out.println("while");
        }*/
//do...while的死循环
/*        do{
            System.out.println("do...while");
        }while (true);
    }
}