Avoid rand() and std::rand() for generating pseudorandom numbers CXX-W2016
The C Standard pseudorandom number generator function rand() has limitations.
While these generators use mathematical algorithms to produce a sequence of
numbers with good statistical properties, they are not genuinely random.
Instead, they rely on a seed value to generate a sequence of numbers that
appears random, but is actually deterministic.
The problem with using the C Standard function rand() is that it makes no
guarantees about the quality of the random sequence produced.
The function have a comparatively short cycle, which means that the
sequence of numbers generated will eventually repeat.
Moreover, the generated numbers may be predictable, making them unsuitable for applications that require high-quality pseudorandom numbers.
This also applies to the std::rand() from C++ standard library.
It is recommended to choose a generator that is sufficient for the specific needs of the application.
Bad practice
#include <cstdlib>
#include <string>
std::string getNewIssueId() {
std::string IssueId("ISSUE-");
// Holds the ID, starting with the characters "ISSUE" followed by a random
// integer in the range [0-100000].
IssueId += std::to_string(std::rand() % 100000);
return IssueId;
}
Recommended
#include <random>
#include <string>
std::string getNewIssueId() {
std::string IssueId("ISSUE-");
std::uniform_int_distribution<int> Dist(0, 100000);
std::random_device RandDev;
std::mt19937 Engine(RandDev());
id += std::to_string(Dist(Engine));
return IssueId;
}