Issues with c++ 11 mersenne_twister_engine class

Question

I have been trying to use the c++ 11 mersenne_twister_engine class( http://www.cplusplus.com/reference/random/mersenne_twister_engine/) to generate numbers in the interval [0,1]

Answer 1

In C++, / on integer numbers results in an integer number. For example 11 / 2 results in 5, not 5.5. In the same way a / b is always zero if a < b.

Your problem is here:

generator()/generator.max()

generator() and generator.max() both return integers and of course, generator.max() >= generator(), so the result is zero (unless you are very lucky to get the max number in which case the result would be one).

To fix this, you can simply cast it:

(double)generator()/generator.max()