Non repeating random number array

Question

I need to make a typical integer filled array with 10 random non repeating numbers from 0 to 20. Also, I need to be able to modify this so I can exclude some random numbers

Answer 1

Well, I could't help it not to post my solution which is storing a sequance of numbers into twice as many random locations first. Then compacts it into the resultting array.

int[] myRandomSet = generateNumbers(20, 10);

...

public int[] generateNumbers(int range, int arrayLenght){
    int tempArray[];
    int resultArray[];
    int doubleLocations;
    Random generator = new Random();

    doubleLocations = range * 2;
    tempArray = new int[doubleLocations];
    resultArray = new int[arrayLenght];

    for (int i=1; i<=range; i++){   
        if (i != 5 && i != 13){  //exclude some numbers
            do{
                r = generator.nextInt(doubleLocations); 
            }while(tempArray[r]!=0);
            tempArray[r] = i; //enter the next number from the range into a random position
        }
    }

    int k = 0;
    for (int i=0; i<(doubleLocations); i++){
        if(tempArray[i] != 0){
            resultArray[k] = tempArray[i]; //compact temp array
            k++;
            if (k == arrayLenght) break;
        }
    }

    return resultArray;
}