Problem - Kevin Tafuro

Solution
Because of the way that floating-point numbers are stored, simply casting bits to a
float will make the distribution nonuniform. Instead, get a random unsigned integer,
and divide.
Discussion
Because integer values are uniformly distributed, you can get a random integer and
divide so that it is a value between 0 and 1:
#include
double spc_rand_real(void) {
return ((double)spc_rand_uint( )) / (double)UINT_MAX;
}
Note that to get a random number between 0 and n, you can multiply the result of
spc_rand_real( ) by n. To get a real number within a range inclusive of the range’s
bounds, do this:
#include
double spc_rand_real_range(double min, double max) {
if (max < min) abort( );
return spc_rand_real( ) * (max - min) + min;
}
11.13 Getting Floating-Point Values with
Nonuniform Distributions
Problem
You want to select random real numbers in a nonuniform distribution.
Solution
The exact solution varies depending on the distribution. We provide implementations
for many common distributions in this recipe.
Discussion
Do not worry if you do not know what a particular distribution is; if you have never
seen it before, you really should not need to know what it is. A uniform distribution
(as discussed in Recipe 11.12) is far more useful in most cases.
Getting Floating-Point Values with Nonuniform Distributions | 609
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