CODE EXAMPLE FOR TYPESCRIPT

constant arguments in c++

#include <iostream>
#include <string>
#include <type_traits>

void function ( int v = 0 ) ; // declaration (header)

// definition of void function ( int )
void function( const int v ) { std::cout << v << '
' ; /* definition */ }

// *** error: redefinition of void function ( int )
// void function( int v ) { std::cout << v << '
' ; /* definition */ }

// declaration and definition
void function_two( const int v ) { std::cout << v << '
' ; /* definition */ }

int main()
{
    function(7) ;

    using function_type = void( int )  ;
    function_type* fn = function ; // fine
    fn = function_two ; // also fine note: const is ignored

    using function_type_const = void( const int ) ; // note: const is ignored
    function_type_const* fnconst = function ; // fine
    fnconst = function_two ; // also fine

    std::cout << std::boolalpha << "void(int) and void( const int ) are the same type: "
              << std::is_same< void(int), void( const int ) >::value << '
' ; // true
}