Java for循环打印菱形
Java代码输出菱形的方法和思路有很多，在此分享一个稍带模块化拆分思想的解决方案，将需要输出的菱形拆分成8个模块（如下图），每个模块独立实现输出。
优点：8个模块之间耦合性降低，灵活性增强。也就是说我们可以独立的控制这8个模块中任意一个模块的输出内容来灵活应对业务逻辑的变更。
按照上图标好的顺序依次实现这8个模块的代码，当1458模块输出为空格时，其中2367模块的组合，就是一个菱形。
思路分析：
1 ######*###### 第一排 模块1[6个"#"]+模块2[1个"*"]+模块3[0个"*"]+模块4[6个"#"]
2 #####***#####
3 ####*****####
4 ###*******###
5 ##*********##
6 #***********#
--------------------------------------------------------
7 ##*********## 第七排 模块5[2个"#"]+模块6[5个"*"]+模块7[4个"*"]+模块8[2个"#"]
8 ###*******###
9 ####*****####
10 #####***#####
11 ######*######
代码示例：
public class Demo {
public static void main(String[] args) {
//为了输出效果在输出时将思路分析中的"#"替换为" "空格输出
for (int i = 1; i <= 11; i++) {
if (i <= 6) {
//当i <=6时打印上三角形
//模块 1
for (int j = 6; j >= i; j--) {
System.out.print(" ");
}
//模块 2
for (int j = 0; j < i; j++) {
System.out.print("*");
}
//模块 3[同一排中模块3的"*"个数总比模块2少1个，所以这里j <i-1作为循环条件即可]
for (int j = 0; j < i - 1; j++) {
System.out.print("*");
}
//模块 4
for (int j = 6; j >= i; j--) {
System.out.print(" ");
}
//换行
System.out.println();
} else {
//当i >6时打印下三角形
//模块 5
for (int j = 7; j <= i + 1; j++) {
System.out.print(" ");
}
//模块 6
for (int j = 11; j >= i; j--) {
System.out.print("*");
}
//模块 7
for (int j = 11; j >= i + 1; j--) {
System.out.print("*");
}
//模块 8
for (int j = 7; j <= i + 1; j++) {
System.out.print(" ");
}
//换行
System.out.println();
}
}
}
}
运行结果：
F:\software\Java\jdk1.8.0_121\bin\java.exe "-javaagent:D:\IntelliJ IDEA 2019.1.4\lib\idea_rt.jar=50753:D:\IntelliJ IDEA 2019.1.4\bin" -Dfile.encoding=UTF-8 -classpath F:\software\Java\jdk1.8.0_121\jre\lib\charsets.jar;F:\software\Java\jdk1.8.0_121\jre\lib\deploy.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\access-bridge-64.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\cldrdata.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\dnsns.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\jaccess.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\jfxrt.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\localedata.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\nashorn.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\sunec.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\sunjce_provider.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\sunmscapi.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\sunpkcs11.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\zipfs.jar;F:\software\Java\jdk1.8.0_121\jre\lib\javaws.jar;F:\software\Java\jdk1.8.0_121\jre\lib\jce.jar;F:\software\Java\jdk1.8.0_121\jre\lib\jfr.jar;F:\software\Java\jdk1.8.0_121\jre\lib\jfxswt.jar;F:\software\Java\jdk1.8.0_121\jre\lib\jsse.jar;F:\software\Java\jdk1.8.0_121\jre\lib\management-agent.jar;F:\software\Java\jdk1.8.0_121\jre\lib\plugin.jar;F:\software\Java\jdk1.8.0_121\jre\lib\resources.jar;F:\software\Java\jdk1.8.0_121\jre\lib\rt.jar;D:\ideastudyspace\spring_study\spring-study\spring-study-aop\target\classes;E:\software\MavenRepository\org\aspectj\aspectjweaver\1.9.4\aspectjweaver-1.9.4.jar;E:\software\MavenRepository\org\springframework\spring-webmvc\5.2.0.RELEASE\spring-webmvc-5.2.0.RELEASE.jar;E:\software\MavenRepository\org\springframework\spring-aop\5.2.0.RELEASE\spring-aop-5.2.0.RELEASE.jar;E:\software\MavenRepository\org\springframework\spring-beans\5.2.0.RELEASE\spring-beans-5.2.0.RELEASE.jar;E:\software\MavenRepository\org\springframework\spring-context\5.2.0.RELEASE\spring-context-5.2.0.RELEASE.jar;E:\software\MavenRepository\org\springframework\spring-core\5.2.0.RELEASE\spring-core-5.2.0.RELEASE.jar;E:\software\MavenRepository\org\springframework\spring-jcl\5.2.0.RELEASE\spring-jcl-5.2.0.RELEASE.jar;E:\software\MavenRepository\org\springframework\spring-expression\5.2.0.RELEASE\spring-expression-5.2.0.RELEASE.jar;E:\software\MavenRepository\org\springframework\spring-web\5.2.0.RELEASE\spring-web-5.2.0.RELEASE.jar;E:\software\MavenRepository\com\alibaba\fastjson\1.2.47\fastjson-1.2.47.jar com.shiguang.test.Demo
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Process finished with exit code 0
业务变更： 打印一个空心菱形
此时只需要将1458模块输出为"*"，2367模块输出为空格即可得到一个空心菱形。
代码示例：
public class Demo2 {
public static void main(String[] args) {
for (int i = 1; i <= 11; i++) {
if (i <= 6) {
//当i <=6时打印上三角形
//模块 1
for (int j = 6; j >= i; j--) {
System.out.print("*");
}
//模块 2
for (int j = 0; j < i; j++) {
System.out.print(" ");
}
//模块 3[同一排中模块3的"*"个数总比模块2少1个，所以这里j <i-1作为循环条件即可]
for (int j = 0; j < i - 1; j++) {
System.out.print(" ");
}
//模块 4
for (int j = 6; j >= i; j--) {
System.out.print("*");
}
//换行
System.out.println();
} else {
//当i >6时打印下三角形
//模块 5
for (int j = 7; j <= i + 1; j++) {
System.out.print("*");
}
//模块 6
for (int j = 11; j >= i; j--) {
System.out.print(" ");
}
//模块 7
for (int j = 11; j >= i + 1; j--) {
System.out.print(" ");
}
//模块 8
for (int j = 7; j <= i + 1; j++) {
System.out.print("*");
}
//换行
System.out.println();
}
}
}
}
运行结果：
F:\software\Java\jdk1.8.0_121\bin\java.exe "-javaagent:D:\IntelliJ IDEA 2019.1.4\lib\idea_rt.jar=50681:D:\IntelliJ IDEA 2019.1.4\bin" -Dfile.encoding=UTF-8 -classpath F:\software\Java\jdk1.8.0_121\jre\lib\charsets.jar;F:\software\Java\jdk1.8.0_121\jre\lib\deploy.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\access-bridge-64.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\cldrdata.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\dnsns.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\jaccess.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\jfxrt.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\localedata.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\nashorn.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\sunec.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\sunjce_provider.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\sunmscapi.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\sunpkcs11.jar;F:\software\Java\jdk1.8.0_121\jre\lib\ext\zipfs.jar;F:\software\Java\jdk1.8.0_121\jre\lib\javaws.jar;F:\software\Java\jdk1.8.0_121\jre\lib\jce.jar;F:\software\Java\jdk1.8.0_121\jre\lib\jfr.jar;F:\software\Java\jdk1.8.0_121\jre\lib\jfxswt.jar;F:\software\Java\jdk1.8.0_121\jre\lib\jsse.jar;F:\software\Java\jdk1.8.0_121\jre\lib\management-agent.jar;F:\software\Java\jdk1.8.0_121\jre\lib\plugin.jar;F:\software\Java\jdk1.8.0_121\jre\lib\resources.jar;F:\software\Java\jdk1.8.0_121\jre\lib\rt.jar;D:\ideastudyspace\spring_study\spring-study\spring-study-aop\target\classes;E:\software\MavenRepository\org\aspectj\aspectjweaver\1.9.4\aspectjweaver-1.9.4.jar;E:\software\MavenRepository\org\springframework\spring-webmvc\5.2.0.RELEASE\spring-webmvc-5.2.0.RELEASE.jar;E:\software\MavenRepository\org\springframework\spring-aop\5.2.0.RELEASE\spring-aop-5.2.0.RELEASE.jar;E:\software\MavenRepository\org\springframework\spring-beans\5.2.0.RELEASE\spring-beans-5.2.0.RELEASE.jar;E:\software\MavenRepository\org\springframework\spring-context\5.2.0.RELEASE\spring-context-5.2.0.RELEASE.jar;E:\software\MavenRepository\org\springframework\spring-core\5.2.0.RELEASE\spring-core-5.2.0.RELEASE.jar;E:\software\MavenRepository\org\springframework\spring-jcl\5.2.0.RELEASE\spring-jcl-5.2.0.RELEASE.jar;E:\software\MavenRepository\org\springframework\spring-expression\5.2.0.RELEASE\spring-expression-5.2.0.RELEASE.jar;E:\software\MavenRepository\org\springframework\spring-web\5.2.0.RELEASE\spring-web-5.2.0.RELEASE.jar;E:\software\MavenRepository\com\alibaba\fastjson\1.2.47\fastjson-1.2.47.jar com.shiguang.test.Demo
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Process finished with exit code 0
转载：https://blog.csdn.net/weixin_45333509/article/details/115253945
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