java中打印实心菱形以及空心菱形的方法

一、打印效果

二、实现代码汇总

为了方便初学者对代码的理解，建议熟练t1到t5为各种三角的打印，然后再进行菱形的打印实现。

package circulationDemo;

import java.util.Scanner;

public class Test {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("请输入要打印的行数：");
        int num = input.nextInt();
        t1(num);// 正直角
        split();
        t2(num);// 倒直角
        split();
        t3(num);// 等腰三角
        split();
        t4(num);// 等腰倒三角++
        split();
        t5(num);// 等腰倒三角--
        split();
        t6(num);// 实心菱形
        split();
        t7(num);// 空心菱形(1)
        split();
        t8(num);// 空心菱形(2)
        split();
        t9(num);// 空心菱形(3)
    }

    private static void t9(int num) {
        for (int k = 1; k <= num; k++) {
            for (int i = 1; i <= (num - k); i++) {
                System.out.print(" ");
            }
            System.out.print("*");
            for (int i = 1; i <= ((k - 2) * 2 + 1); i++) {
                System.out.print(" ");
            }
            if (k != 1) {
                System.out.print("*");
            }
            System.out.println();
        }
        for (int k = num-1; k >= 1; k--) {
            for (int i = 1; i <= (num - k); i++) {
                System.out.print(" ");
            }
            System.out.print("*");
            for (int i = 1; i <= ((k - 2) * 2 + 1); i++) {
                System.out.print(" ");
            }
            if (k != 1) {
                System.out.print("*");
            }
            System.out.println();
        }
    }

    private static void t8(int num) {
        // 上半部分
        for (int i = 1; i <= num; i++) {
            // 打印上半部分空格
            for (int j = 1; j <= num - i; j++) {
                System.out.print(" ");
            }
            // 打印原本实心的*部分
            for (int j = 1; j <= 2 * i - 1; j++) {
                // 仅在一行的开头和末尾打印*
                if (j == 1 || j == 2 * i - 1) {
                    System.out.print("*");
                } else {
                    System.out.print(" ");
                }
            }
            System.out.println();
        }
        // 下半部分
        for (int i = 1; i <= num - 1; i++) {
            for (int j = 1; j <= i; j++) {
                System.out.print(" ");
            }
            for (int j = 1; j <= 2 * (num - i - 1) + 1; j++) {
                if (j == 1 || j == 2 * (num - i - 1) + 1) {
                    System.out.print("*");
                } else {
                    System.out.print(" ");
                }
            }
            System.out.println();
        }

    }

    private static void t7(int num) {
        // 打印上半部分
        for (int i = 1; i <= num; i++) {
            // 打印空格
            for (int j = 1; j <= (num - i); j++) {
                System.out.print(" ");
            }
            // 打印*的个数
            if (i == 1) {
                System.out.print("*");
            } else {
                System.out.print("*");
                // 打印菱形里的空格
                for (int j = 1; j <= (2 * i - 3); j++) {
                    System.out.print(" ");
                }
                System.out.print("*");
            }

            System.out.println();
        }
        // 打印下半部分
        for (int i = num - 1; i > 0; i--) {
            // 打印空格
            for (int j = 1; j <= (num - i); j++) {
                System.out.print(" ");
            }
            // 打印*的个数
            if (i == 1) {
                System.out.print("*");
            } else {
                System.out.print("*");
                // 打印菱形里的空格
                for (int j = 1; j <= (2 * i - 3); j++) {
                    System.out.print(" ");
                }
                System.out.print("*");
            }
            System.out.println();
        }
    }

    private static void t6(int num) {
        // 上半部分
        for (int i = 1; i <= num; i++) {
            for (int j = 1; j <= num - i; j++) {
                System.out.print(" ");
            }
            for (int j = 1; j <= 2 * i - 1; j++) {
                System.out.print("*");
            }
            System.out.println();
        }
        // 下半部分
        for (int i = 1; i <= num - 1; i++) {
            for (int j = 1; j <= i; j++) {
                System.out.print(" ");
            }
            for (int j = 1; j <= 2 * (num - 1 - i) + 1; j++) {
                System.out.print("*");
            }
            System.out.println();
        }
    }

    private static void t5(int num) {
        for (int i = num; i > 0; i--) {
            for (int j = 1; j <= num - i; j++) {
                System.out.print(" ");
            }
            for (int j = 1; j <= 2 * i - 1; j++) {
                System.out.print("*");
            }
            System.out.println();
        }
    }

    private static void t4(int num) {
        for (int i = 1; i <= num; i++) {
            for (int j = 1; j <= i - 1; j++) {
                System.out.print(" ");
            }
            for (int j = 1; j <= 2 * (num - i) + 1; j++) {
                System.out.print("*");
            }
            System.out.println();
        }
    }

    private static void t3(int num) {
        for (int i = 1; i <= num; i++) {
            for (int j = 1; j <= num - i; j++) {
                System.out.print(" ");
            }
            for (int j = 1; j <= 2 * i - 1; j++) {
                System.out.print("*");
            }
            System.out.println();
        }
    }

    private static void split() {
        System.out.println("---------------");
    }

    private static void t2(int num) {
        for (int i = 1; i <= num; i++) {
            for (int j = 1; j <= num - i + 1; j++) {
                System.out.print("*");
            }
            System.out.println();
        }
    }

    private static void t1(int num) {
        for (int i = 1; i <= num; i++) {
            for (int j = 1; j <= i; j++) {
                System.out.print("*");
            }
            System.out.println();
        }
    }

}