C : How can I create random numbers certain range? [duplicate]

Question

I want to create some specific random, such that from 10 to 20.

rand()%20;

is create from 0 to 19

So create a random number from 0 to 10 (inclusive) and then add 10 to it. — David Schwartz
– David Schwartz, Commented Oct 24, 2015 at 0:15

Justin Meiners · Accepted Answer · 2015-10-24 00:21:03Z

0

Apply some simple arithmetic

int val = min + (rand() % range);

Where range is (max - min) + 1

A random number betweeen 10-20 is just a random number between 0-10 shifted +10

answered Oct 24, 2015 at 0:15

Justin Meiners

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9 Comments

Modulo division is not the best idea from the perspective of uniformity of resulting distribution.

@void_ptr True, but this works fine for most uses.

@chux Good catch. Thanks

@JustinMeiners and its this attitude which is why software has so much bugs.

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