CODEWITHSUNDEEP
calgorithmrandomnumbers
THE DOCTOR
THE DOCTOR

Reputation: 4555

Random Number Calculation Logic

I'm looking at someone else's code and trying to figure out the logic behind what they wrote. What would one use the following random number calculation for? 

return ( ((rand() % 10000)+1) <= Rate * 100);

Rate here is being used for a user-specified value representing an overall percentage of when a certain event occurs.

Upvotes: 0

Views: 105

Answers (2)

Mario
Mario

Reputation: 36487

The left part of the expression returns a random number between 1 and 10,000 (due to the + 1; otherwise it would be between 0 and 9,999).

Rate can then be used to determine the effective chance of the expression being true. The higher Rate is, the higher the chance of returning true.

Since Rate is multiplied with 100, you're able to determine the Rate using 0 to 100 (essentially percentages) with Rate = 0 never and Rate = 100 always returning true.

Upvotes: 2

mathematician1975
mathematician1975

Reputation: 21351

To generate a random integer between 1 and 10000 inclusive. As for the comparison with Rate*100 who can say as you do not specify what this means.

Upvotes: 2

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