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-   -   Java linklist Code (http://www.go4expert.com/forums/java-linklist-code-t7516/)

cyrow 25Nov2007 02:49

Java linklist Code
 
Requirements
1) read from output file
eg: 1222222 + 2333333
3444444 - 9999999
6666555 * 7
0

2) For addition and sutraction, Number1 and Number2 should be large integers and must be stored in a link list.
eg.output = 1222222 + 2333333 =
454444444(answer)

3) For multiplication, Number1 should be stored in a link list and the small integer in a variable.
output = 66666555 * 7 =
43343555555(answer)

4) Write to output file

Code
When I try to read from the output file, this error is generated
!!Error :Variable last might not have been initialize
Help me to clarify the issue becuase i don't think I have to initialize "last" as it has already been declared as a node type.

//Jkd1.6.0_02

Code:

import java.io.*;
import java.util.*;

class Node{
        int bigInt;
        Node next;
       
      Node(){
        bigInt = 0;
                next = null;
        }
       
        public Node(int bigInt){
                bigInt = 0;
                next = null;
        }
       
}
public class BuildList{
        public static void main(String[] args)throws IOException{
       
        Scanner in = new Scanner(new FileReader("input.txt"));       
        FileWriter out = new FileWriter("output.txt") ;
       
        Node top, np, last;
        top = null;
       
        //Reading data from input.txt
        int bigInt = in.nextInt();
        while(bigInt!=0){
               
                if (bigInt > 100){//only bigInt numbers are added to the list for add, subtract and multiply
                       
                        np = new Node(bigInt);
                if (top==null){
                        top = np;
                }else{
                        last.next = np;
                        last = np;
                        bigInt = in.nextInt();
                }
        }                       
        }
                       
}//end main
}//end class check



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