[ 实现 ] 利用Java画三角形！

import com.sun.org.apache.bcel.internal.generic.IF_ACMPEQ; import java.text.MessageFormat; import java.util.Random; public class tuxing { public static void main(String[] args) { //直角三角形 //外层控制行 for (int i = 1; i <= 5; i++) { //内层控制列 for (int j = 1; j <= i; j++) { System.out.println("*"); } System.out.println(); } //直角三角形 //外层控制行 for (int i = 1; i <= 5; i++) { //内层控制列 for (int j = 1; j <= 6 - i; j++) { System.out.println("*"); } System.out.println(); } //等腰三角形 //正的 for (int i = 1; i <= 5; i++) { for (int j = 1; j <= 6 - i; j++) { System.out.print(" "); } for (int j = 1; j <= 2 * i - 1; j++) { System.out.print("*"); } System.out.println(); } //等腰三角形正的空心的 for (int i = 1; i <= 5; i++) { for (int j = 1; j <= 6 - i; j++) { System.out.print(" "); } for (int j = 1; j <= 2 * i - 1; j++) { boolean first = i == 1 || i == 5 || j == 1 || j == 2 * i - 1; System.out.print(first ? "*" : " "); } System.out.println(); } //等腰三角形 //倒的 for (int i = 1; i <= 5; i++) { for (int j = 1; j <= i - 1; j++) { System.out.print(" "); } for (int j = 1; j <= 11 - 2 * i; j++) { System.out.print("*"); } System.out.println(); } //等腰三角形 //倒的空心的 for (int i = 1; i <= 5; i++) { for (int j = 1; j <= i - 1; j++) { System.out.print(" "); } for (int j = 1; j <= 11 - 2 * i; j++) { boolean first = i == 1 || i == 5 || j == 11 - 2 * i || j == 1; System.out.print(first ? "*" : " "); } System.out.println(); } //菱形 //第一种方法 for (int i = 1; i <= 5; i++) { for (int j = 1; j <= 5 - i; j++) { System.out.print(" "); } for (int j = 1; j <= 2 * i - 1; j++) { System.out.print("*"); } System.out.println(); } for (int i = 1; i <= 4; i++) { for (int j = 1; j <= i; j++) { System.out.print(" "); } for (int j = 1; j <= 9 - 2 * i; j++) { System.out.print("*"); } System.out.println(); } //第二种方法 for (int i = -4; i <= 4; i++) { for (int j = 1; j <= Math.abs(i); j++) { System.out.print(" "); } for (int j = 1; j <= 9 - 2 * (Math.abs(i)); j++) { System.out.print("*"); } System.out.println(); } //沙漏 for (int i = -4; i <= 4; i++) { for (int j = 1; j <= 4 - Math.abs(i); j++) { System.out.print(" "); } for (int j = 1; j <= 1 + 2 * (Math.abs(i)); j++) { System.out.print("*"); } System.out.println(); } //沙漏空心 for (int i = -4, ABSI; i <= 4; i++) { ABSI = Math.abs(i); for (int j = 1; j <= 4 - ABSI; j++) { System.out.print(" "); } for (int j = 1, N = 2 * ABSI + 1; j <= N; j++) { boolean first = ABSI == 4 || j == 1 || j == N; System.out.print(first ? "*" : " "); } System.out.println(); } } }