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Java Insertion sort problem 
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#1
Aug3011, 10:45 PM

P: 96

So i havent done java in about two years, its been a while since ive seen arrays. THe assignment is to fix a program that was given to me. I found one error but in the insertion sort part i cant get it to run the while loop. I cant make any fundamental changes to the program, basically i just have to fix the error in the while loop to get it running.
any pointers or advice would be appreciated, just need a kick in the right direction. below is the program import java.io.*; // for BufferedReader import java.util.*; // for StringTokenizer public class Prog1Original { // A simple program with no classes public static void main(String[] args) throws IOException { int number[] = new int[100]; int ct, num, size, i, j, insel; BufferedReader stdin = new BufferedReader( new InputStreamReader(System.in) ); System.out.print("Input integers: "); size = 0; // The smallest index of an array is always 0 String inputLine = stdin.readLine(); // All input must be on a single line StringTokenizer input = new StringTokenizer(inputLine); while (input.hasMoreTokens()) { // extract the integers from the input line num = Integer.parseInt(input.nextToken()); number[size] = num; size = size + 1; } System.out.println(); System.out.print("The original numbers: "); for (ct = 0; ct < size; ct++) { System.out.print(number[ct]); System.out.print(" "); } System.out.println(); // "Insertion Sort" the numbers for (i = 1; i < size; i++) { // Starting with the second array element insel = number[i]; j = i; while ( (number[j] > insel) && (j >= 0) ) { // shift larger elements right number[j + 1] = number[j]; j = j  1; } number[j] = insel; // insert the number to its proper place } System.out.print("The sorted numbers: "); // Output the sorted array for (ct = 0; ct < size; ct ++) { System.out.print(number[ct]); System.out.print(" "); } System.out.println(); } } 


#2
Aug3111, 12:20 AM

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P: 21,215

I added (code) and (/code) tags (but in square brackets) to preserve your original formatting.



#3
Aug3111, 12:40 AM

P: 96

i put in System.out.print(" " + j); into the while loop to see if it would print out anything while doing the loop. my thinking was that if it did then the program goes through the loop but it didnt print that out which leads me to think that it doesnt go through the loop.



#4
Aug3111, 01:03 AM

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P: 21,215

Java Insertion sort problem
Right. If you don't have a debugger to work with, or do have one but don't know how to use it, put a print statement just before the start of the loop to display the values of j and number[j].
If you have a debugger available, it would be a very good idea to learn how to use it. 


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