for(int i = str.length();i > 0;i--){ if(i%3 == 0){ str.insert(str.length()-i,","); } }
public?class?HelloWorld?{ ????public?static?void?main(String[]?args)?{ //?創(chuàng)建一個空的StringBuilder對象 StringBuilder?str?=?new?StringBuilder(); ???????? //?追加字符串 str.append("jaewkjldfxmopzdm"); ????????//?從后往前每隔三位插入逗號 ????????for(int?i?=?str.length();i?>?0;i--){ ????????????if(i%3?==?0){ ????????????????str.insert(str.length()-i,","); ????????????} ????????} ???????? ????????//?將StringBuilder對象轉換為String對象并輸出 System.out.print(str.toString()); } }
2014-11-15
把i- -改成i-=3,不就不用if語句了嗎