Control statements - loop structure (the while)

 

Loop structure:

　　Cyclic structure may reduce the workload of the source code written in duplicate, to describe the implementation of certain repeat algorithm, a program loop structure Structured Programming a computer to play the most expertise.

　　Loop structure can be seen as a combination of a conditional statement and the statement of the steering back.

　　Loop structure of the four elements:

　　　　1. loop variable

　　　　2. loop

　　　　3. cycling conditions

　　　　4. iterator

 

while loop:

　　while loop is the most basic cycle, while the statement before the start of first determines the result of a Boolean expression, if it is true (true), the loop body is executed, otherwise, out of the loop.

 

 

　　expression:

the while (Boolean expressions) {     // the while the first determination of the Boolean expressions, the true start of the loop is 
    the loop body             // iteration of the loop 
    iterator             // iterations (typically from unary plus (++), or from minus (-)), the iteration is finished after the return to continue the next cycle is determined whether 
}

 

Example:

　　① while loop and the calculated 0-100:

package exercise;

/ ** 
 * @author Liu will
 * While loop
 * (Cycle four conditions must be met: 1, initialization; 2, condition judgment; 3, loop; 4, iteration)
 * While loop: 0 to 100 and calculates how much
 */
public class TestWhile {
    
        public static void main(String[] args) {

        int a = 0;
        int sum = 0;
        while(a<=100) {
            sum += a;
            a++;
        }
        System.out.println("0~100的和为："+sum);

    }
}

 

　　②使用while循环计算0-100间的所有偶数和与基数和：

package com.lxj.cnblogs;

/**
 * @author 刘小将
 * while循环
 *  计算0-100间的所有偶数和与基数和
 */
public class TestWhile{
    
    public static void main(String[] args){
        
        int oddSum = 0;        //奇数
        int evenSum = 0;    //偶数
        int i = 0;            //声明循环变量
        while(i <=100){
            if(i % 2 !=0){
                oddSum += i;
                i++;
            }else{
                evenSum += i;
                i++;
            }
        }
        System.out.println("oddSum is:"+oddSum);
        System.out.println("evenSum is:"+evenSum);
    }
}