public?class?HelloWorld?{
????public?static?void?main(String[]?args)?{
//?創(chuàng)建一個(gè)空的StringBuilder對(duì)象
StringBuilder?str=?new?StringBuilder();
????????
//?追加字符串
str.append("jaewkjldfxmopzdm");
????????//?從后往前每隔三位插入逗號(hào)
for?(int?i?=?str.length()-3;i>0;i=i-3)
????????str.insert(i,',');
????????
????????
????????//?將StringBuilder對(duì)象轉(zhuǎn)換為String對(duì)象并輸出
System.out.print(str.toString());
}
}for (int i = str.length()-3;i>0;i=i-3)什么意思？
java 中的 StringBuilder 類的常用方法,for (int i = str.length()-3;i>0;i=i-3)讀不懂？？
Jerrylinusa
2015-11-21 20:06:51