For some kid game, I have an array of size 10 of bool type. I got a random number between 1 to 10 and what I like to do, Is initialize only that number of cells in TRUE but in random order.
For example, If my random number is 4, I would like outputs like:
F T F F F T T F F T
T F F T T T F F F F
Is there an easy way to do it in C#?
Note, I know all the syntax (Init an array, work with random and all), I have a problem to find a short algorithm that does it.
Generate:
int length = 10;
int numberOfTrue = 4;
bool[] array = Enumerable
.Range(0, length)
.Select(index => index < numberOfTrue)
.ToArray();
And shuffle (e.g. with Fisher–Yates algorithm):
Random random = new Random();
...
for (int i = array.Length - 1; i >= 1; --i) {
int from = random.Next(i + 1);
var h = array[i];
array[i] = array[from];
array[from] = h;
}
Just like in real life, create the number of trues you want, the number of falses that you need and then put them in a bag and shuffle them:
var random = new Random();
int numberOfTruths = 7;
int numberOfFalsehoods = 10 - numberOfTruths;
var truths = Enumerable.Repeat(true, numberOfTruths);
var falsehoods = Enumerable.Repeat(false, numberOfFalsehoods);
var arrayOfBools = truths.Concat(falsehoods).OrderBy(x => random.Next()).ToArray();
Another solution, if you don't want to use lists.
var rndBoolArray = new bool[10];
Random rnd = new Random();
int rndTrueCount = rnd.Next(1, 10); // Generate random number for the amount of true values in the array
for(int i = 0; i < rndTrueCount; i++)
{
int rndIndex = rnd.Next(0, 9); // Generate random number for the index
if(rndBoolArray[rndIndex] == false) // If the value at this position is not already true
rndBoolArray[rndIndex] = true;
else
rndTrueCount++; // We have to do one more loop, if the value of the array at the random index was already true
}
true. That looks like an algorithm to me.