[Ajuda Com Um Programinha Em C++]

Este é um programa para calcular o máximo divisor comum entre dois números:

#include <iostream>
#include <cmath>

using namespace std;

float mdc(float num_a, float num_b);

int main(int argc,char* argv[]) {
    
    float num_a;
    float num_b;
    float resul;
    
    cout << "\nDigite um valor para A: ";
    cin >> num_a;
    cout << "\nDigite um valor para B: ";
    cin >> num_b;
    
    resul = mdc( num_a, num_b );
    cout << "\nResultado: "<< resul << "\n";
    
    return 0;
    
}

float mdc( float num_a, float num_b ) {
        
    if( num_b == 0 ) {
            
        return num_a;
        
    }
                
    return mdc( num_b, fmod( num_a, num_b ));
        
}

Durante a compilação ocorre o seguinte erro: $gcc -o mdc mdc.cpp

/tmp/ccPSCwBy.o(.text+0x19): In function `main':
: undefined reference to `std::cout'
/tmp/ccPSCwBy.o(.text+0x1e): In function `main':
: undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
/tmp/ccPSCwBy.o(.text+0x2d): In function `main':
: undefined reference to `std::cin'
/tmp/ccPSCwBy.o(.text+0x32): In function `main':
: undefined reference to `std::basic_istream<char, std::char_traits<char> >::operator>>(float&)'
/tmp/ccPSCwBy.o(.text+0x42): In function `main':
: undefined reference to `std::cout'
/tmp/ccPSCwBy.o(.text+0x47): In function `main':
: undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
/tmp/ccPSCwBy.o(.text+0x56): In function `main':
: undefined reference to `std::cin'
/tmp/ccPSCwBy.o(.text+0x5b): In function `main':
: undefined reference to `std::basic_istream<char, std::char_traits<char> >::operator>>(float&)'
/tmp/ccPSCwBy.o(.text+0x8d): In function `main':
: undefined reference to `std::cout'
/tmp/ccPSCwBy.o(.text+0x92): In function `main':
: undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
/tmp/ccPSCwBy.o(.text+0x9b): In function `main':
: undefined reference to `std::basic_ostream<char, std::char_traits<char> >::operator<<(float)'
/tmp/ccPSCwBy.o(.text+0xa4): In function `main':
: undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
/tmp/ccPSCwBy.o(.text+0x11e): In function `__static_initialization_and_destruction_0(int, int)':
: undefined reference to `std::ios_base::Init::Init[in-charge]()'
/tmp/ccPSCwBy.o(.text+0x14d): In function `__tcf_0':
: undefined reference to `std::ios_base::Init::~Init [in-charge]()'
/tmp/ccPSCwBy.o(.gnu.linkonce.t._ZSt4fmodff+0x10): In function `std::fmod(float, float)':
: undefined reference to `fmodf'
/tmp/ccPSCwBy.o(.eh_frame+0x11): undefined reference to `__gxx_personality_v0'
collect2: ld returned 1 exit status

Desde já agradeço a todos..

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