Java输出空心菱形

用Java编写一个能输出空心菱形的小程序：

public static void main(String[] args) throws NewException{
		// TODO Auto-generated method stub 
		int num = 3;
		for (int i = 0; i < num; i++) {
			for(int j=0;j<num-i-1;j++){
				System.out.print(" ");
			}
			for(int a=0;a<i*2-1;a++){
				if(a==0||a==i*2+1){
					System.out.print("*");
				}
				System.out.print(" ");
			}
			System.out.println("*");
		}
		for (int i = num-1; i > 0; i--) {
			for(int j=num-i;j>0;j--){
				System.out.print(" ");
			}
			for(int a=0;a<i*2-3;a++){
				if(a==0||a==i*2+1){
					System.out.print("*");
				}
				System.out.print(" ");
			}
			System.out.println("*");
		}
}

另一种方法：

public static void main(String[] args) throws NewException{
		// TODO Auto-generated method stub
		
		int num = 3;
		for (int i = 1; i <= num; i++) {
			for (int j = 1; j <= num - i; j++) {
				System.out.print(" ");
			}
			for (int k = 1; k <= 2 * i - 1; k++) {
				if (k == 1 || k == 2 * i - 1) {
					System.out.print("*");
				} else {
					System.out.print(" ");
				}
			}
			System.out.println();
		}
		for (int i = 1; i < num; i++) {
			for (int j = 1; j <= i; j++)
				System.out.print(" ");
			int count = 2 * (num - i) - 1;
			for (int k = 0; k < count; k++) {
				if (k == 0 || k == count - 1)
					System.out.print("*");
				else
					System.out.print(" ");
			}
			System.out.println("");
		}
	
	}