Starting with C++11 you should no longer use rand() as RNG. For more background information see S.T.L.'s "rand() Considered Harmful" talk from 2013.

Instead, you want to use the <random> header with std::uniform_real_distribution.

#include <random> #include <iostream> class RandomNumberGenerator { std::random_device m_randomDevice{}; std::mt19937 m_engine{m_randomDevice()}; public: // Generates a random float in the range [low, high] float Generate(float low, float high) { return std::uniform_real_distribution<float>{low, high}(m_engine); } }; int main() { auto rng = RandomNumberGenerator{}; for (auto i = 0u; i < 20u; ++i) { std::cout << rng.Generate(1.2f, 10.4f) << "\n"; } } 

Starting with C++11 you should no longer use rand() as RNG. For more background information see S.T.L.'s "rand() Considered Harmful" talk from 2013.

Instead, you want to use the <random> header with std::uniform_real_distribution.

#include <random> #include <iostream> class RandomNumberGenerator { std::random_device m_randomDevice{}; std::mt19937 m_engine{m_randomDevice()}; public: // Generates a random float in the range [low, high) float Generate(float low, float high) { return std::uniform_real_distribution<float>{low, high}(m_engine); } }; int main() { auto rng = RandomNumberGenerator{}; for (auto i = 0u; i < 20u; ++i) { std::cout << rng.Generate(1.2f, 10.4f) << "\n"; } }