怎么做
public class HelloWorld {
??? public static void main(String[] args) {
// 創(chuàng)建一個(gè)空的StringBuilder對(duì)象
// 追加字符串
str.append("jaewkjldfxmopzdm");
??????? // 從后往前每隔三位插入逗號(hào)
??????? // 將StringBuilder對(duì)象轉(zhuǎn)換為String對(duì)象并輸出
System.out.print(str.toString());
}
}
2017-10-25
StringBuilder str = new StringBuilder();
for (int i = str.length() - 3; i > 0; i -= 3) {
str.insert(i, ",");
}