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();
         }
     }

 }