#include <array>#include <cstddef>#include <iomanip>#include <iostream>#include <span>#include <string_view>#include <vector> void print(std::string_view rem="",std::size_t size_of=0,std::size_t extent=0){if(rem.empty()){std::cout<<"name │ sizeof │ extent\n""─────┼────────┼────────\n";return;}std::cout<<std::setw(4)<< rem<<" │ "<<std::setw(6)<< size_of<<" │ ";if(extent==std::dynamic_extent)std::cout<<"dynamic";elsestd::cout<< extent;std::cout<<'\n';} int main(){int a[]{1,2,3,4,5};     print();std::span s1{std::begin(a),std::end(a)};// guide (1)    print("s1", sizeof s1, s1.extent); std::span s2{std::begin(a),3};// guide (1)    print("s2", sizeof s2, s2.extent); #if __cplusplus > 202302Lstd::span s3{std::begin(a),std::integral_constant<std::size_t,2>{}};// guide (1)    print("s3", sizeof s3, s3.extent);#endif // C++26 std::span s4{a};// guide (2)    print("s4", sizeof s4, s4.extent); std::span<int> s5{a};// does not use a guide, makes a dynamic span    print("s5", sizeof s5, s5.extent); std::array arr{6,7,8};std::span s6{arr};// guide (3)    print("s6", sizeof s6, s6.extent);    s6[0]=42;// OK, element_type is 'int' conststd::array arr2{9,10,11};std::span s7{arr2};// guide (4)    print("s7", sizeof s7, s7.extent);// s7[0] = 42; // Error: element_type is 'const int' std::vector v{66,69,99};std::span s8{v};// guide (5)    print("s8", sizeof s8, s8.extent);}

name │ sizeof │ extent─────┼────────┼────────  s1 │     16 │ dynamic  s2 │     16 │ dynamic  s3 │      8 │ 2  s4 │      8 │ 5  s5 │     16 │ dynamic  s6 │      8 │ 3  s7 │      8 │ 3  s8 │     16 │ dynamic