Files

import java.util.Scanner;
// import scanner
import java.io.File;
public class hw3pt2 {
     public static void main( String[] args ) throws Exception {
        //this is the part where you read the file
        File file = new File("catalog.txt");
        Scanner input = new Scanner(file);
        int array[] = new int[101];
        // the array is 101 spaces because we ignore the zero spot
        int i = 1;
        // makes me skip the zero spot and move to the first 
        // now I can start a while loop that stores the data I need for the code
        while(input.hasNextLine()){ // while there is a next line
            String temp = input.nextLine();
            String tempArray[] = temp.split(" ");
            // making each line after a space its own array becuase I only want
            // the ids
            array[i] = Integer.parseInt(tempArray[0]); 
            // changing a string into a integer
            i++;
        }
        Scanner scan = new Scanner(System.in);
        System.out.print("Enter starting position in file (1 - 100): ");
        int startp = scan.nextInt(); // start p = starting position
        System.out.print(startp + " ->");
        int nextp = startp;         // nextp = next position
        int next = 1; // skip the zero spot
        while(startp != array[nextp]){
           // next keeps track of the amount of links so i can have a count at the 
           // end
            nextp = array[nextp];
            System.out.print(" " + nextp);
            next++;
            // adding one to the count of next 
        }
        System.out.println(" ->"+ startp); 
        System.out.println("The chain is " + next + " links long.");
        
     }
}