determine input type, C++ (vc++)

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//Microsoft (R) C/C++ Optimizing Compiler Version 19.00.23506 for x64

#include <iostream>
#include <string>
#include <cctype>
#include <sstream>
#include <iomanip>

std::string trim( std::string str )
{
    // remove trailing white space
    while( !str.empty() && std::isspace( str.back() ) ) str.pop_back() ;

// return residue after leading white space
    std::size_t pos = 0 ;
    while( pos < str.size() && std::isspace( str[pos] ) ) ++pos ;
    return str.substr(pos) ;
}

bool is_integer( std::string str ) // trimmed string
{
    std::size_t pos  = 0 ;
    try
    {
        std::stoll( str, std::addressof(pos), 0 ) ;
        if( pos == str.size() ) return true ;
    }

catch( const std::exception& ) {}
    return false ;
}

bool is_floating_point( std::string str ) // trimmed string
{
    std::size_t pos  = 0 ;
    try
    {
        std::stold( str, std::addressof(pos) ) ;
        if( pos == str.size() ) return true ;
    }

catch( const std::exception& ) {}
    return false ;
}

enum type_t { INTEGER, FLOATING_POINT, CHARACTER, STRING, NOTHING };

std::ostream& operator<< ( std::ostream& stm, type_t type )
{
   static const std::string desc[] = { "INTEGER", "FLOATING_POINT", "CHARACTER", "STRING", "NOTHING" };
   if( type < INTEGER || type > NOTHING ) type = NOTHING ;
   return stm << desc[type] ;
}

type_t type_of_input( std::string str )
{
    str = trim(str) ;

if( is_integer(str) ) return INTEGER ;
    else if( is_floating_point(str) ) return FLOATING_POINT ;
    else if( str.empty() ) return NOTHING ;
    else if( str.size() == 1 ) return CHARACTER ;
    else return STRING ;
}

int main()
{
    std::stringbuf sbuf( "+1 1 -1 -1234 +0x1b2f -1.234e+5 +1234. 1.23e-4 a b a1 1abcd hello" ) ;
    std::cin.rdbuf( std::addressof(sbuf) ) ;

std::string input ;
    while( std::cin >> input )
        std::cout << std::quoted(input) << ' ' << type_of_input(input) << '\n' ;

std::cout << std::quoted( "    " ) << ' ' << type_of_input( "    " ) << '\n' ;
}

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Compilation time: 2,18 sec, absolute running time: 0,34 sec, absolute service time: 2,53 sec