for循环实例

Posted 2021-06-25 爱钓渔的企鹅

9*9乘法表

public class chengFaDemo {
    public static void main(String[] args) {
        for (int i = 1; i <=9; i++) {
            for (int j = 1; j <= i; j++) {
                System.out.print(j+"*"+i+"="+i*j+"\\t");

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

1*1=1	
1*2=2	2*2=4	
1*3=3	2*3=6	3*3=9	
1*4=4	2*4=8	3*4=12	4*4=16	
1*5=5	2*5=10	3*5=15	4*5=20	5*5=25	
1*6=6	2*6=12	3*6=18	4*6=24	5*6=30	6*6=36	
1*7=7	2*7=14	3*7=21	4*7=28	5*7=35	6*7=42	7*7=49	
1*8=8	2*8=16	3*8=24	4*8=32	5*8=40	6*8=48	7*8=56	8*8=64	
1*9=9	2*9=18	3*9=27	4*9=36	5*9=45	6*9=54	7*9=63	8*9=72	9*9=81

增强for循环

public class forDemo02 {
    public static void main(String[] args) {
       int [] names={1,2,3,4,5};
        for (int i = 0; i < 5; i++) {
            System.out.print(names[i]+"\\t");
        }
        System.out.println();
       for(int x:names){
           System.out.print(x+"\\t");
       }
    }
}

1	2	3	4	5	
1	2	3	4	5	

两个for循环的效果一样

打印三角形

public class testDemo {
    public static void main(String[] args) {
        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();
        }
    }
}

     *
    ***
   *****
  *******
 *********