SOME COMPUTER STUFF ON C,JAVA,TALLY,BCA,SOLVED PAPERS

import java.io.*; import java.lang.*; public class adder { public static void main(String args[])throws Exception { DataInputStream dd= new DataInputStream(System.in); System.out.println("Enter two Numbers"); String a=dd.readLine(); String b=dd.readLine(); int i=0,sum=0,carry=0,total=0; String s=""; //assuming they are of equal length for(i=b.length()-1;i>=0;i--) { char a1=a.charAt(i); char a2=b.charAt(i); total+=(int)a1+(int)a2-96; switch(total) { case 0: sum=0;carry=0;break; case 1: sum=1;carry=0;break; case 2: sum=0;carry=1;break; case 3: sum=1;carry=1;break; } s=sum+s; total=carry; } if(carry!=0) s=carry+s; System.out.println("sum is:"+s); } }