Java打印三角形练习

打印5行实心三角形

public class TestDemo1 {
    public static void main(String[] args) {
        //打印三角形 5行
        for (int i = 1; i <= 5; i++) {
            for (int j = 5; j > i; j--) {
                System.out.print(" ");

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

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

        }


    }
}

打印任意行空心三角形

public class TestDemo2 {
    public static void main(String[] args) {
        //打印5行空心三角形
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入需要打印的三角形的行数：");
        int x = scanner.nextInt();
        for (int i = 1; i <= (x-1); i++) {
            for (int j = (x-1); j >= i; j--) {
                System.out.print(" ");
            }
            System.out.print("*");

            for (int j = 1;j < i;j++){
                System.out.print(" ");
            }
            
            for (int j = 2; j < i; j++) {
                System.out.print(" ");
            }
            
            if (i>=2){
                System.out.print("*");
            }
            
            System.out.println("\n");
            }
        
        for (int i = 1; i <= (2*x-1); i++) {
            System.out.print("*");
        }
        
        scanner.close();
        }
    }