I would like to generate a random floating point number between 2 values. What is the best way to do this in C#?
C# Random – How to Generate a Random Number in C#
c++floating-pointrandom
c++floating-pointrandom
I would like to generate a random floating point number between 2 values. What is the best way to do this in C#?
Best Answer
The only thing I'd add to Eric's response is an explanation; I feel that knowledge of why code works is better than knowing what code works.
The explanation is this: let's say you want a number between 2.5 and 4.5. The range is 2.0 (4.5 - 2.5).
NextDouble
only returns a number between 0 and 1.0, but if you multiply this by the range you will get a number between 0 and range.So, this would give us random doubles between 0.0 and 2.0:
But, we want them between 2.5 and 4.5! How do we do this? Add the smallest number, 2.5:
Now, we get a number between 0.0 and 2.0; if you add 2.5 to each of these values we see that the range is now between 2.5 and 4.5.
At first I thought that it mattered if b > a or a > b, but if you work it out both ways you'll find it works out identically so long as you don't mess up the order of the variables used. I like to express it with longer variable names so I don't get mixed up: