for循环

//打印九九乘法表
public class demo06 {
    public static void main(String[] args) {
        for (int j = 1; j <=9; j++) {
            for (int i = 1; i <= j; i++) {
                System.out.print(j+"*"+i+"="+(i*j) +"\t");
            }
            System.out.println();

        }
    }
}

 

//100以内奇数偶数和
public class demo04 {
    public static void main(String[] args) {
        int s=0;
        int a=0;
        for (int i = 0; i < 100; i++) {
            if (i%2==0){
                s+=i;
            }else{
                a+=i;
            }

        }
        System.out.println("偶数和为"+s);
        System.out.println("奇数和为"+a);

    }
}

//打印输出1000以内可以被5 整除的数
public class demo05 {
    public static void main(String[] args) {
        for (int i = 0; i < 1000; i++) {
            if (i%5 ==0){
                System.out.print(i+"\t");
            }
            if (i%15==0){
                System.out.println("\n");
            }

        }
    }
}