编程练习1——字符串操作（字符串压缩）

import java.util.*;
public class Stri {

public static void main(String[] args)
{
Scanner s = new Scanner(System.in);
String a = s.next();
StringBuilder str = new StringBuilder();
int num=1;
for(int i=1;i<a.length();i++)
{
if(a.charAt(i)==a.charAt(i-1))
{
num++;

}
else
{
str.append(a.charAt(i-1));
str.append(num);
num=1;
}

if(i==a.length()-1)
{
str.append(a.charAt(i));
str.append(num);
}

}
if(str.length()>=a.length())
{
System.out.println(a);
}
else
System.out.println(str.toString());

}
}