Question

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How do you generate a random double uniformly distributed between 0 and 1 from C++?

I’m trying to figure out how to generate a random number between 0 and pi, but the usual method won’t work because mod does integer division:

double num = rand() % 2*M_PI;

How would I go about doing this?

Thanks.

Answer 1

Generate a random number between 0 and 1, and then multiply the result by 2*M_PI.

If you have a uniform distribution between 0 and 1, you will also have a uniform distribution between 0 and 2*M_PI, to the limit of precision available in the numeric type you are using.

For generating a random uniform double between 0 and 1, see the answer suggested by @dasblinkenlight in his comment.