题解 | #动态字符串#
动态字符串
https://www.nowcoder.com/practice/e2c51a6f126b41f9be403376c7adea15
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
String str = scanner.next();
//write your code here......
StringBuilder newstr = new StringBuilder(str);//将固定的字符串变为可变的字符串
for(int i = str.length()-3; i>0 ;i-=3){
newstr.insert(i,",");
}
System.out.print(newstr.toString());
}
}