public class StringDecode { public static void main(String[] args) { String a="a2bc3d1"; StringBuffer b=new StringBuffer(); StringBuffer c=new StringBuffer(); for(int i=0;i<a.length();i++){ if(!(a.charAt(i)>='0' && a.charAt(i)<='9')){ b.append(a.charAt(i)); }else{ int n=a.charAt(i)-'0'; c.append(add(b,n)); b.delete(0, b.length()); } } System.out.println(c); } public static StringBuffer add(StringBuffer s,int n){ StringBuffer s2=new StringBuffer(); if(n==1){ return s; }else{ for(int i=0;i<n;i++){ s2.append(s); } return s2; } } }