Java Array Integer manipulation

Question

Cant seem to figure out why my array isnt outputting the correct value. The sum prints out as the first integer in the array. I wanted the sum of all the integers in the array. Any ideas what could be wrong? I attempted to convert the int to a string to be sent out.

  //Add values of Integers
  int i; int sum = 0; 
  for(i = 0; i < intarray.length; i++){  
      sum = sum + intarray[i];
  }

  String sumOut =  Integer.toString(sum);
  System.out.println( "to Client: " + sumOut);
  toclient.writeBytes("Sum = " +sumOut+'\n');

You can drop String sumOut = ... and use sum when printing, the toString method is called implicitly anyway. — Konrad Reiche
– Konrad Reiche, Commented Jul 26, 2012 at 0:16
try to print out sum by using System.out.println(sum); immediately after the for loop — arunmoezhi
– arunmoezhi, Commented Jul 26, 2012 at 0:17

duffymo · Accepted Answer · 2012-07-26 00:18:18Z

2

Here's how I'd do it:

package cruft;

/**
 * IntegerSum description here
 * @author Michael
 * @link
 * @since 7/25/12 8:14 PM
 */
public class IntegerSum {
    public static void main(String[] args) {
        int [] values = new int[args.length];
        for (int i = 0; i < args.length; ++i) {
            values[i] = Integer.valueOf(args[i]);
        }
        System.out.println(String.format("sum = %d", sum(values)));
    }

    public static int sum(int [] values) {
        int sum = 0;
        for (int value : values) {
            sum += value;
        }
        return sum;
    }
}

answered Jul 26, 2012 at 0:18

duffymo

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8 Comments

Code-Apprentice Over a year ago

Which is essentially what the OP posted (other than not with a for-each loop). Unfortunately, the OP didn't post how he is initializing the array.

duffymo Over a year ago

Not really - what's all that stuff about converting the sum to a String and whatnot? I think mine is cleaner: the sum is encapsulated into a single method that can be called in other contexts, and it doesn't mingle summing and output. These are the small details of which coding is made.

Code-Apprentice Over a year ago

Granted, your design is cleaner. I was commenting on the logic. (And yes, I agree that there is no need to convert the int to a String explicitly...see my answer.)

duffymo Over a year ago

The loop isn't written using the standard Java idiom; it fails to leverage the += operator. That's a lot of commentary for such a small snippet.

Code-Apprentice Over a year ago

Which is all syntactic sugar that still doesn't help answer the question of why the original code doesn't work in the first place. The problem is very likely in the array initialization.

|

Code-Apprentice · Accepted Answer · 2012-07-26 00:24:28Z

2

Your code looks correct. Try printing out the contents of intarray to be sure what it contains. Also, how do you put values into intarray. Post some code to show us. Perhaps the array is not populated correctly.

Also, there is no need for the line

String sumOut =  Integer.toString(sum);

Java will convert an int to a String automatically when you use the + operator, for example:

System.out.println("to Client:" + sum);

edited Jul 26, 2012 at 0:24

answered Jul 26, 2012 at 0:16

Code-Apprentice

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1 Comment

Mark Nelson Over a year ago

Thanks this fixed the problem by its self. The problem was that when I used .toString it only displayed the first park of the array. When I used just sum it displayed the total. Thanks!

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