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Composition

 
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Composition
chronoTrigger
7 May, 2008 - 09:41 AM
Post #1

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I would like to know how do I pass data into the composition class through constructor.

For example I have two classes.

CODE

class myFile
{
public:
myFile(string fName);


private:
string fileName;

};


class student
{
public:
student(string name, string fName);

private:
string studentName;
myFile writeToFile;
}



In my main function when the constructor is called it will pass student name and file name and also I would like the file name will be passed to myFile class constructor.

how can I do that?

thanks
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skaoth
RE: Composition
7 May, 2008 - 10:38 AM
Post #2

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What you are trying to do is commonly referred to as constructor initialization.
When an object is created, the constructor of class allows you to initialize your class before the actual object is technically created.

This is how you would do this

CODE

class student
{
    public:
        student(string name, string fName) : writeToFile(fName)
        {
            ....
        }
};
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chronoTrigger
RE: Composition
7 May, 2008 - 12:21 PM
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thanks for your reply, and I tried like you suggested, but it gives error though. It's saying WroteToFile is not a base or member. This error message maybe it assumes that I'm calling my base class constructor using inheritance, but I don't use inheritnance.

But I found a solution to it though, but not sure if it's correct or not. Inside my student constructor, I just allocate new memory using the keyword new of myFile type.

CODE

student::student(string name, string fName)
{
    name = "\0";
    myFile newFile = new myFile(fName);

}



}
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