std::seed_seq:: seed_seq

From cppreference.com
C++
Numerics library
Common mathematical functions
Mathematical special functions (C++17)
Mathematical constants (C++20)
Basic linear algebra algorithms (C++26)
Data-parallel types ( simd ) (C++26)
Floating-point environment (C++11)
Complex numbers
Numeric array ( valarray )
Pseudo-random number generation
Factor operations
(C++17)
(C++17)
Interpolations
(C++20)
(C++20)
Saturation arithmetic
(C++26)
(C++26)
(C++26)
(C++26)
(C++26)

Generic numeric operations
Bit operations
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
Pseudo-random number generation
Random number distributions
Uniform distributions
(C++11)
(C++11)
(C++11)
Bernoulli distributions
(C++11)
(C++11)
(C++11)
(C++11)
Poisson distributions
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
Normal distributions
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
Sampling distributions
(C++11)
(C++11)
(C++11)
std::seed_seq
seed_seq ( ) noexcept ;
(1) (since C++11)
seed_seq ( const seed_seq & ) = delete ;
(2) (since C++11)
template < class InputIt >
seed_seq ( InputIt begin, InputIt end ) ;
(3) (since C++11)
template < class T >
seed_seq ( std:: initializer_list < T > il ) ;
(4) (since C++11)
1) The default constructor. After construction, v is empty.
2) The copy constructor is deleted: std::seed_seq is not copyable.
3) Constructs a std::seed_seq with the values in the range [ begin , end ) . Equivalent to default-initializing v  followed by for ( InputIt s = begin ; s ! = end ; ++ s )
v  . push_back ( modseed ( * s ) ) ; , where mod_seed(x)=x mod 2 32 .
If std:: iterator_traits < InputIt > :: value_type is not an integer type, the program is ill-formed.
If InputIt does not satisfy the requirements of LegacyInputIterator , the behavior is undefined.
4) Equivalent to seed_seq ( il. begin ( ) , il. end ( ) ) . This constructor enables list-initialization from the list of seed values.
This overload participates in overload resolution only if T is an integer type.

Parameters

begin, end - the pair of iterators denoting the initial seed sequence
il - the initial seed sequence

Example

Run this code 
#include <iterator>
#include <random>
#include <sstream>
 
int main()
{
    std::seed_seq s1; // default-constructible
    std::seed_seq s2{1, 2, 3}; // can use list-initialization
    std::seed_seq s3 = {-1, 0, 1}; // another form of list-initialization
    int a[10] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    std::seed_seq s4(a, a + 10); // can use iterators
    std::istringstream buf("1 2 3 4 5"); 
    std::istream_iterator<int> beg(buf), end;
    std::seed_seq s5(beg, end); // even stream input iterators
}

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG 2180 C++11 all constructors were non-throwing only overload ( 1 ) is non-throwing
LWG 3422 C++11 1. overload ( 1 ) was not noexcept
2. overload ( 4 ) was not constrainted 		1.made noexcept
2. constrained
Retrieved from " https://en.cppreference.com/mwiki/index.php?title=cpp/numeric/random/seed_seq/seed_seq&oldid=177243 "