Question

This code is buggy but can’t figure out why … want to populate an array with 7 unique random integers without using arraylists or linq! I know the logic is not okay…

class Program
{
    static void Main(string[] args)
    {    int current;
         int[] numbers = new int[7];  // size of that array 
         Random rNumber = new Random();
         current = rNumber.Next(1, 50);
         numbers[0] = current;
         Console.WriteLine("current number is {0}", current);
         for (int i=1;i<7;i++)
         {
             current = rNumber.Next(1, 50);
             for (int j = 0; j < numbers.Length; j++)
             {
                 do
                 {
                     if (current == numbers[j])
                     {
                         Console.WriteLine("Duplicate Found");
                         current = rNumber.Next(1, 50);
                     }
                     else
                     {   
                         numbers[j++] = current;
                         break;
                     }
                 }while (current == numbers[j]);

             }//inner for

         }//outer for
         for (int l = 0; l < 7; l++) // DISPLAY NUMBERS
         {
             Console.WriteLine(numbers[l]);
         }

    }// main
 }//class

Answer 1

I presume you are looking for random numbers, so the other answer is not what you are looking for.

There are a couple of issues here.

• The inner loop is testing for duplicates. However, it is looking from 0 through the end of the array since it is using numbers.length. This should probably be i, to compare with already set values. numbers.length is always 7 regardless of whether or not you set any of the elements.

• the assignment is using j, so presuming the first element is not a duplicate, it will be overwritten each time. That should be numbers[i] = current;. No ++ necessary as the for is handling the incrementing.

• if you determine that a number is a duplicate, j should be reset to zer to check against the entire list again rather than having the while in the middle.

Without a complete rewrite, the changes will look something like this:

     for (int i=1;i<7;i++)
     {
         current = rNumber.Next(1, 50);
         for (int j = 0; j < i; j++)  //----------------- loop through set values
         {
             if (current == numbers[j])
             {
                 Console.WriteLine("Duplicate Found");
                 current = rNumber.Next(1, 50);
                 j = 0; // -----------------------reset the counter to start over
             }
         }//inner for

         // if we got here there is no duplicate --------------------------------
         numbers[i] = current;

     }//outer for

(Please note that I have not tested this code, just added the changes)