В чем причина ошибки линковки в NetBeans (gcc 4.9)?

#include <iostream>
#include <cstdlib>
#include <math.h>
using namespace std;
 
int main()
{
    double x,y,f,a,b;
    int k;
    cout <<"Vvedite x "; cin >> x;
    cout <<"Vvedite y "; cin >> y;
    cout << "Viberite f: 1 - sh(x), 2 - x^2, 3 - exp(x) "; cin >> k;
    switch(k)
    {
        case 1: f=sinh(x); break;
        case 2: f=pow(x,2); break;
        case 3: f=exp(x); break;
        default: cout <<"Ne vybrana funkciya"; return 1;
    }
    a=pow(x,3);
    if (a>0) {
        b=log(pow(f,3));
    } else
    if (a<0) {
        b=tan(a)+f;
    } else b=pow(fabs((pow(y,3)-a)), 1.0/3);
    cout << "Resultat = "<< b << endl;
    
    
}

/tmp/user/1000/ccV1Iml1.o: In function `main':
main1.cpp:(.text+0x1a): undefined reference to `std::cout'
main1.cpp:(.text+0x1f): 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*)'
main1.cpp:(.text+0x2e): undefined reference to `std::cin'
main1.cpp:(.text+0x33): undefined reference to `std::istream::operator>>(double&)'
main1.cpp:(.text+0x43): undefined reference to `std::cout'
main1.cpp:(.text+0x48): 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*)'
main1.cpp:(.text+0x57): undefined reference to `std::cin'
main1.cpp:(.text+0x5c): undefined reference to `std::istream::operator>>(double&)'
main1.cpp:(.text+0x6c): undefined reference to `std::cout'
main1.cpp:(.text+0x71): 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*)'
main1.cpp:(.text+0x80): undefined reference to `std::cin'
main1.cpp:(.text+0x85): undefined reference to `std::istream::operator>>(int&)'
main1.cpp:(.text+0xff): undefined reference to `std::cout'
main1.cpp:(.text+0x104): 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*)'
main1.cpp:(.text+0x1ea): undefined reference to `std::cout'
main1.cpp:(.text+0x1ef): 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*)'
main1.cpp:(.text+0x201): undefined reference to `std::ostream::operator<<(double)'
main1.cpp:(.text+0x20c): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&)'
main1.cpp:(.text+0x212): undefined reference to `std::ostream::operator<<(std::ostream& (*)(std::ostream&))'
/tmp/user/1000/ccV1Iml1.o: In function `__static_initialization_and_destruction_0(int, int)':
main1.cpp:(.text+0x244): undefined reference to `std::ios_base::Init::Init()'
main1.cpp:(.text+0x259): undefined reference to `std::ios_base::Init::~Init()'
collect2: error: ld returned 1 exit status