while loop in java

• The complete format of the while loop:

  初始化语句;
  while (条件判断语句) {
        
        
  	循环体语句;
      条件控制语句;
  }
  

• While loop execution process:

  ①Execute the initialization statement

  ②Execute the conditional judgment statement to see if the result is true or false

  ​ If it is false, the loop ends

  ​ If it is true, continue execution

  ③Execute loop body statement

  ④Execute conditional control statement

  ⑤Back to ②Continue

while loop case-Mount Everest

public class WhileTest {
    
    
    public static void main(String[] args) {
    
    
		//定义一个计数器，初始值为0
		int count = 0;
		//定义纸张厚度
		double paper = 0.1;
		//定义珠穆朗玛峰的高度
		int zf = 8844430;
		//因为要反复折叠，所以要使用循环，但是不知道折叠多少次，这种情况下更适合使用while循环
		//折叠的过程中当纸张厚度大于珠峰就停止了，因此继续执行的要求是纸张厚度小于珠峰高度
		while(paper <= zf) {
    
    
			//循环的执行过程中每次纸张折叠，纸张的厚度要加倍
			paper *= 2;
			//在循环中执行累加，对应折叠了多少次
			count++;
		}
		//打印计数器的值
		System.out.println("需要折叠：" + count + "次");
    }
}

Loop statement-dowhile loop

• Full format:

  初始化语句;
  do {
        
        
  	循环体语句;
  	条件控制语句;
  }while(条件判断语句);
  

• Implementation process:

  ① Execute initialization statement

  ② Execute loop body statement

  ③ Execute conditional control statement

  ④ Execute the conditional judgment statement to see if the result is true or false

  If it is false, the loop ends

  If it is true, continue execution

  ⑤ Back to ② Continue

public class DoWhileDemo {
    
    
    public static void main(String[] args) {
    
    
        //需求：在控制台输出5次"HelloWorld"
		//for循环实现
		for(int i=1; i<=5; i++) {
    
    
			System.out.println("HelloWorld");
		}
		System.out.println("--------");
		//do...while循环实现
		int j = 1;
		do {
    
    
			System.out.println("HelloWorld");
			j++;
		}while(j<=5);
    }
}