More efficient way of checking for a duplicate random output?-CodePudding

trying to change the position of some buttons using the random function, am currently using a setup of 3 while loops for each of my buttons. it works but i was wondering if there's a more efficient way of preventing the random outputs from being the same than what i have? (im pretty new to programming so please let me know how i could improve. thanks!!:D )

Random r = new Random();

int location = r.Next(0, 3);
btnCorrect.Location = new Point(xCoordinates[location], positionY);

int location2 = r.Next(0, 3);
while (location2 == location)
{
    location2 = r.Next(0, 3);
}

btnIncorrect1.Location = new Point(xCoordinates[location2], positionY);

int location3 = r.Next(0, 3);
while (location3 == location|| location3==location2)
{
    location2 = r.Next(0, 3);
}

btnIncorrect2.Location = new Point(xCoordinates[location2], positionY);

CodePudding user response：

The usual solution for such tasks is to use Fisher–Yates shuffle. In your case you can shuffle indexes:

var rnd = new Random();
var indexes = Enumerable.Range(0, 3).ToArray();
for (int i = 0; i < indexes.Length; i  )
{
    
    var j = i   rnd.Next(indexes.Length - i);
    var element = indexes[i];
    indexes[i] = indexes[j];
    indexes[j] = element;
}

// use indexes to select elements
// i.e. location = indexes[0], location1 = indexes[1], location2 = indexes[2]

CodePudding user response：

This is another variation of @gurustron 's answer. This solution uses Random for sorting the values

var rnd = new Random();
var indexes = Enumerable.Range(0, 3).OrderBy(_ => rnd.Next(1000)).ToArray();