Java 用循环嵌套语句生成*三角形阵列

思路1：按顺序生成星和空格。
思路2：先全部生成星，然后消除多余的星

思路1：

package com.MyJava;

import java.util.Scanner;

public class For {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int k = scan.nextInt();

		int i = 1, j = 1;
		while (i <= k) {
			for (j = 1; j <= k - i; j++) {
				System.out.print(" ");
			}
			for (j = 1; j <= 2 * i - 1; j++) {
				System.out.print("*");
			}
			System.out.print("\n");
			i++;
		}
	}
}

思路2

package com.MyJava;

import java.util.Scanner;

public class For {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int k = scan.nextInt();

		int i, j;
		for (i = 1; i <= k; i++) {
			for (j = 1; j <= 2*k-1; j++) {
				if (j >= k - i + 1 & j <= k + i - 1) {
					System.out.print("*");
					}
					else {
						System.out.print(" ");
					}	
				}
				System.out.print("\n");
		}
	}
}

思路2

package com.MyJava;

import java.util.Scanner;

public class For {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int k = scan.nextInt();

		int i = 1, j = 1;
		for (i = 1; i <= k; i++) {
			for (j = 1; j <= 2 * k - 1; j++) {
				while (j >= k - i + 1 & j <= k + i - 1) {
					System.out.print("*");
					j++;
				}
				System.out.print(" ");
			}
			// System.out.print(" ");
			System.out.print("\n");
		}

	}
}