CODEWITHSUNDEEP
c++classconstructor
RnD
RnD

Reputation: 1069

C++ fstream in class

I started studying classes and now I faced a problem. I'm trying to put all my variables into a class, but I get errors:

main.cpp|6|error: expected identifier before string constant| 
main.cpp|6|error: expected ',' or '...' before string constant|
main.cpp|7|error: expected identifier before string constant|
main.cpp|7|error: expected ',' or '...' before string constant|

Although when I make them global everything works fine

    class Kauliukas{

        ifstream inFile("inFile.in");
        ofstream outFile("outFile.out");
        int n, akutes[100],k=0;

        void ivedimas();
        void skaiciavimas();
        void isvedimas();
};

What's the problem?

Upvotes: 1

Views: 10103

Answers (2)

Paul Manta
Paul Manta

Reputation: 31577

In pre-C++11 versions of the language you can only declare variables inside the class body, you can't also initialize them (ifstream inFile is a declaration; ifstream inFile("infile.in") is a declaration and an initialization).

You have to do it like this:

class Kauliukas
{
  public:
    Kauliukas();

  private:
    ifstream inFile;
};

Kauliukas::Kauliukas()    // This is the constructor definition
    : inFile("infile.in") // This is called an initialization list
{
    // ...
}

Upvotes: 2

CapelliC
CapelliC

Reputation: 60014

Initialization goes in the constructor. That's different than, for instance, C#. You must define a constructor like

class Kauliukas {
public:
    Kauliukas() : inFile("inFile.in"), outFile("outFile.out"), k(0) {}
private:
    ifstream inFile;
    ofstream outFile;
    int n, akutes[100],k;

    void ivedimas();
    void skaiciavimas();
    void isvedimas();
};

Upvotes: 6

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