根據使用者輸入的數字，產生一個以星號組成的塔狀圖形

gistfile1.java

import java.util.Scanner;

class test {

	/**
	 * @param args
	 */
	public static void main(String[] args) throws java.lang.Exception {
		// TODO Auto-generated method stub
		try {
			System.out.print("Enter a number: ");  // 準備讓使用者輸入數字
			Scanner scanner = new Scanner(System.in); // 取得使用者的輸入
			String target = scanner.next();
			int a = Integer.parseInt(target);  // 將使用者的輸入轉換成integer
			if (a % 2 == 0) {  // 當發現使用者的輸入為偶數時拋出例外
				throw new Exception("Must be an odds");
			}
			up(a);  // 負責產生結果的兩個functions
			bottom(a);
		} catch (Exception e) {
			System.out.println("error:");
			System.out.println(e.getMessage());
		}
	}
	
	public static void up (int a) {
		int i = 1;

		for (; i < a; i += 2) {
			int j = (a - i) / 2;
			for (int k = 0; k < a; k++) {
				if (k < j || k > (i + j - 1))	System.out.print(" ");
				else System.out.print("*");
			}
			System.out.println("");
		}
	}
	
	public static void bottom (int a) {

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

}