FizzBuzz GUI

main.cpp

#include <iostream>
#include <string>
#define sometimes if

bool is( std::string text )
{
    return ! text.empty();
}

std::string number( int x )
{
    return std::to_string( x );
}

std::string buzz( int x )
{
    return 0 == x % 5 ? "Buzz":"";
}

std::string fizz( int x )
{
    return 0 == x % 3 ? "Fizz":"";
}

std::string fizz_or_buzz( int x )
{
    return fizz(x) + buzz(x);
}

std::string fizzbuzz( int x )
{
    return is( fizz_or_buzz( x ) ) ? fizz_or_buzz( x ) : number( x );
}

bool enough( std::ostream & os, int x )
{
    os << fizzbuzz( x ) << " "; return x != 99;
}

void is_enough( std::ostream & os, int x = 1 )
{
    sometimes ( enough( os, x ) ) is_enough( os, x + 1 );
}

#ifdef LEST

#include "lest.hpp"

bool can_be_divided_by_3( int x ) { return 0 == x % 3; }
bool can_be_divided_by_5( int x ) { return 0 == x % 5; }

bool can_be_divided_by_3_not_5(   int x ) { return   can_be_divided_by_3( x ) && ! can_be_divided_by_5( x ); }
bool can_be_divided_by_5_not_3(   int x ) { return   can_be_divided_by_5( x ) && ! can_be_divided_by_3( x ); }
bool can_be_divided_by_3_and_5(   int x ) { return   can_be_divided_by_3( x ) &&   can_be_divided_by_5( x ); }
bool cannot_be_divided_by_3_or_5( int x ) { return ! can_be_divided_by_3( x ) && ! can_be_divided_by_5( x ); }

auto range( int first, int last, std::function<bool(int)> pred ) -> std::vector<int> 
{
    std::vector<int> result;
    for ( int i = first; i != last; ++i )
        if ( pred( i ) )
            result.push_back( i );
    return result;
}

const lest::test specification[] =
{
    CASE( "A number itself is produced if it cannot be divided by 3 or 5" )
    {
        for ( auto x : range( 1, 100, cannot_be_divided_by_3_or_5 ) )
        {
            EXPECT( std::to_string( x ) == fizzbuzz( x ) );
        };
    },

    CASE( "Fizz is produced for numbers that can be divided by 3 but not by 5" )
    {
        for ( auto x : range( 1, 100, can_be_divided_by_3_not_5 ) )
        {
            EXPECT(  x > 0 );
            EXPECT( "Fizz" == fizzbuzz( x ) );
        };
    },

    CASE( "Buzz is produced for numbers that can be divided by 5 but not by 3" )
    {
        for ( auto x : range( 1, 100, can_be_divided_by_5_not_3 ) )
        {
            EXPECT(  x > 0 );
            EXPECT( "Buzz" == fizzbuzz( x ) );
        };
    },

    CASE( "FizzBuzz is produced for numbers that can be divided by 3 and 5" )
    {
        for ( auto x : range( 1, 100, can_be_divided_by_3_and_5 ) )
        {
            EXPECT(  x > 0 );
            EXPECT( "FizzBuzz" == fizzbuzz( x ) );
        };
    },
};

int main( int argc, char * argv[] )
{
    return lest::run( specification, argc, argv );
}

#elif defined( GUI )

#include <sstream>
#include <windows.h>

int main()
{
    std::ostringstream os; is_enough( os );
    MessageBox( nullptr, os.str().c_str(), "FizzBuzz GUI", MB_ICONSTOP | MB_OK );
}

#else 

int main()
{
    is_enough( std::cout );
}

#endif // TEST

// g++        -Wall -std=c++11 -o main.exe main.cpp && main
// g++ -DGUI  -Wall -std=c++11 -o main.exe main.cpp && main
// g++ -DLEST -Wall -std=c++11 -o main.exe main.cpp && main

s/devided/divided/g

@paulburlumi Thanks! Corrected.