Generates a random floating point number in range[​0​, 1).

To generate enough entropy,generate_canonical() will callg() exactly\(\small k\)k times, where\(\small k = \max(1, \lceil \frac{b}{\log_2 R} \rceil)\)k = max(1, ⌈ b / log2 R ⌉) and

• b=std::min(Bits,std::size_t{std::numeric_limits<RealType>::digits}),
• R= g.max()- g.min()+1.

[edit]Parameters

[edit]Return value

Floating point value in range[​0​, 1).

[edit]Exceptions

None except from those thrown byg.

[edit]Notes

Some existing implementations have a bug where they may occasionally return1.0 ifRealType isfloatGCC #63176LLVM #18767MSVC STL #1074. This isLWG issue 2524.

[edit]Example

#include <iostream>#include <random> int main(){std::random_device rd;std::mt19937 gen(rd());for(int n=0; n<10;++n)std::cout<< std::generate_canonical<double,10>(gen)<<' ';std::cout<<'\n';}

0.208143 0.824147 0.0278604 0.343183 0.0173263 0.864057 0.647037 0.539467 0.0583497 0.609219

[edit]See also

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