Can't access a vector inside a class

[Sy0XoG1T]

Alright I'm trying to use a vector inside of a class but I'm getting unresolved externals and I'm not sure on how to fix it.

class Sfx
{
private:
	RenderWindow & renderwindow;
	vector<SoundBuffer> File;

public:
	Sfx(RenderWindow & Screen): renderwindow(Screen){}
	void LoadSfxFile(std::string filename);
};

void Sfx::LoadSfxFile(std::string filename)
{
	File.at(File.size()-1).LoadFromFile(filename);
}

Getting errors from trying to access File in LoadSfxFile.

[Disch]

Can you post the error message?

[Sy0XoG1T]

Error 1 error LNK2019: unresolved external symbol "__declspec(dllimport) public: bool __thiscall sf::SoundBuffer::LoadFromFile(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (__imp_?LoadFromFile@SoundBuffer@sf@@QAE_NABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) referenced in function "public: void __thiscall Sfx::LoadSfxFile(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >)" (?LoadSfxFile@Sfx@@QAEXV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) main.obj

Error 2 fatal error LNK1120: 1 unresolved externals

[Sy0XoG1T]

Wait I think it's a problem with SFML's SoundBuffer class. int works perfectly fine in the same situation.

[Disch]

The problem has nothing to do with vector.

The linker can't find the LoadFromFile function. Are you linking to the necessary libraries?

Also, this is unrelated, but:

File.at(File.size()-1).LoadFromFile(filename);  // instead of this

File.back().LoadFromFile(filename); // you can do this