package com.sf.struct;

public class For01 {
    //for 是支持迭代的一种通用结构。最有效，最灵活
    //for 的循环次数在执行权确定
    public static void main(String[] args) {
        int a = 1;//初始化条件

        while(a<=100){//条件判断
            System.out.println(a);//循环体
            a += 2;//迭代
        }
        for(int i=1;i<=100;i++){
            System.out.println(i);
        }
    }
}

package com.sf.struct;

public class For02 {
    //求1-100内奇数和偶数的和
    public static void main(String[] args) {
        //oddSum  奇数的和
        int oddSum = 0;
        //evenSum  偶数的和
        int evenSum = 0;
        for (int i = 1; i < 100; i++) {
            if (i%2!=0){
                oddSum += i;
            }else{
                evenSum += i;
            }
        }
        System.out.println(oddSum);
        System.out.println(evenSum);
    }
}

package com.sf.struct;

public class For03 {
    //输出1-1000内能被5整除的数，并每输出3个就换一次行
    public static void main(String[] args) {
        for (int i = 1; i <= 1000; i++) {
            if (i%5==0){
                System.out.print(i+"\t");
                // \t 制表
            }
            if (i%(5*3)==0){
                //每输出三次换行相当于每次除15换一次
                System.out.print("\n");
                // \n换行
            }
        }
    }
}

package com.sf.struct;

public class For04 {

    //99乘法表
    public static void main(String[] args) {
        /*for (int j = 1; j <= 9; j++) {
            for (int i = 1; i <= j; i++) {
                System.out.print(i+"*"+j+"="+(j*i)+"\t");
            }
            System.out.println();
        }*/

        for (int j = 9; j >=1 ; j--) {
            for (int i = 1; i <= j; i++) {
                System.out.print(i+"*"+j+"="+(j*i)+"\t");

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

package com.sf.struct;

public class For05 {
    //增强for循环  多用于数组和集合
    //在JDK5时引用
    public static void main(String[] args) {
        //定义数组
        int[] numbers = {10,20,30,40,50};

        //遍历数组
        for (int x:numbers){
            System.out.println(x);
        }

        for(int i = 0;i<5;i++){
            System.out.println(numbers[i]);
        }
    }
}