顺序选择循环

for循环

练习1：计算0-100之间的奇数和和偶数和

 

package com.yang.struct;
public class ForDemo01
{   //练习1：计算0到100之间的奇数和和偶数和
    public static void main(String[] args) {
        int oddSum = 0;
        int evenSum = 0;
        for (int i = 0; i <= 100; i++) {
            if (i%2 == 0){
                evenSum += i;
            }
            else {
                oddSum += i;
            }


        }
        System.out.println(oddSum);
        System.out.println(evenSum);
    }
}

练习2：用while或for循环输出1-1000之间能被5整除的数，并且每行输出三个

package com.yang.struct;
public class ForDemo02 {
    public static void main(String[] args) {
        int m = 0;
        for (int i = 0; i <= 1000; i++) {
            if (i%5 == 0){
                System.out.print(" "+i);
                ++m;
                if (m%3 == 0){
                    System.out.println("\n");
                }

            }

        }
    }
}

练习3：打印九九乘法表

package com.yang.struct;

public class TestDemo01 {
    public static void main(String[] args) {
        //打印三角形 5行
        for (int i = 1; i <= 5; i++) {
            for (int j =5; j >= i;j--){
                System.out.print(" "); }
            for (int j = 1; j <= i;j++){
                System.out.print("*"); }
            for (int j = 1; j < i;j++){
                    System.out.print("*");
                }
            System.out.println();
        }

    }
}

//打印101-150之间所有的质数

package com.yang.struct;

public class LabelDemo
{
    public static void main(String[] args) {
        //打印101-150之间所有的质数
        outer:for (int i = 101;i <= 150;i++){
            for (int j = 2;j < i/2;j++){
                if (i % j == 0){
                   continue outer;
                }
            }
            System.out.println(i+" ");
        }
    }
}

break和continue的区别：