java螺旋填数三角形_Java - 使用嵌套的for-loops创建一个带有数字的三角形

I have homework to make a triangle that looks like this:

1

2 1 2

3 2 1 2 3

4 3 2 1 2 3 4

5 4 3 2 1 2 3 4 5

6 5 4 3 2 1 2 3 4 5 6

I have been able to create almost half the triangle with the following code:

public static void main(String[] args) {

for (int i = 1; i <= 6; i++) {

for (int j = 1; j <= i; j++)

System.out.print(j + " ");

System.out.println();

}

}

I have been unable to figure out how to mirror the other half of the triangle with my code to look like the triangle above. The instructor hinted that using the for loop with the tab return \t is the way to do this.

解决方案

try

for (int i = 1; i <= 6; i++) {

for (int j = 6; j > i; j--) {

System.out.print(" ");

}

for (int j = i; j > 1; j--) {

System.out.print(j + " ");

}

for (int j = 1; j <= i; j++) {

System.out.print(j + " ");

}

System.out.println();

}

output

1

2 1 2

3 2 1 2 3

4 3 2 1 2 3 4

5 4 3 2 1 2 3 4 5

6 5 4 3 2 1 2 3 4 5 6