java for循环九九乘法表、等腰三角形、菱形、沙漏

文章目录

• for循环
• • 九九乘法表
  • 等腰三角形
  • 菱形
  • 沙漏

for循环

外层for控制每一列的数
内层fou控制每一行的数

九九乘法表

for(int i=1;i<=9;i++){
    for(int j=1;j<=i;j++){
        System.out.print(j+"*"+i"="+(j*i)" ");
    }
    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 

等腰三角形

for(int i=1;i<=9;i++){
	for(int j=9;j>=i;j--){
	    System.out.print("*");
	}
	for(int k=1;k<=2*i-1;k++){
	    System.out.print("0");
	}
	    System.out.println();
}

*********0
********000
*******00000
******0000000
*****000000000
****00000000000
***0000000000000
**000000000000000
*00000000000000000

菱形

for (int i = 1; i <=9; i++) {
			for (int j = 9; j >=i; j--) {
				System.out.print("*");
			}
			for (int k = 1; k <= 2*i-1; k++) {
				System.out.print("0");
			}
			System.out.println();
		}
		for (int i = 1; i <= 9; i++) {
			for (int j = 1; j <=i; j++) {
				System.out.print("*");
			}
			for (int j = 9*2; j >=i*2 ; j--) {
				System.out.print("0");
			}
			System.out.println();
		}

*********0
********000
*******00000
******0000000
*****000000000
****00000000000
***0000000000000
**000000000000000
*00000000000000000
*00000000000000000
**000000000000000
***0000000000000
****00000000000
*****000000000
******0000000
*******00000
********000
*********0

沙漏

		for (int i = 1; i <= 9; i++) {
			for (int j = 1; j <=i; j++) {
				System.out.print("*");
			}
			for (int j = 9*2; j >=i*2 ; j--) {
				System.out.print("0");
			}
			System.out.println();
		}
		for (int i = 1; i <=9; i++) {
			for (int j = 9; j >=i; j--) {
				System.out.print("*");
			}
			for (int k = 1; k <= 2*i-1; k++) {
				System.out.print("0");
			}
			System.out.println();
		}

*00000000000000000
**000000000000000
***0000000000000
****00000000000
*****000000000
******0000000
*******00000
********000
*********0
*********0
********000
*******00000
******0000000
*****000000000
****00000000000
***0000000000000
**000000000000000
*00000000000000000