Explanation of Syntax for Class Functions

[Chris Hammond]

In the header file "PayOff1.h"(pasted at the bottom of the message) the PayOff class is created. In the file "PayOff1.cpp," the PayOff function is actually defined.

I understand that "PayOff::PayOff(...)" starts the definition, but why is there a colon after that instead of a parenthesis? I have read most of O'REilly's "Practical C++ Programming," and I cannot seem to find an explanation for what is going on here.

PayOff::PayOff(double Strike_, OptionType TheOptionsType_)
:
Strike(Strike_), TheOptionsType(TheOptionsType_)
{
}

double PayOff::operator ()(double spot) const
{
switch (TheOptionsType)
{
case call :
return max(spot-Strike,0.0);

case put:
    return max(Strike-spot,0.0);

default: 
    throw("unknown option type found.");

}

}

// PayOff1.h

ifndef PAYOFF_H

define PAYOFF_H

class PayOff
{

public:

enum  OptionType {call, put};
PayOff(double Strike_, OptionType TheOptionsType_);
double operator()(double Spot) const;

private:

double Strike;
OptionType TheOptionsType;

};

endif

[cpns]

It is an example of a "member initialization list". Look that or just "initializer list" or similar. If you book uses English spelling it will be an "initialisation list".

Alternatively it the following links explain it:

http://msdn.microsoft.com/en-us/magazine/cc301399.aspx
http://www.cprogramming.com/tutorial/initialization-lists-c++.html

You can google for many more examples now you know what it is called.

[Chris Hammond]

Thanks again. That was very helpful.

[cpns]

... despite the fact that I typed it in something only approximating English. Mutt be tired.