Calling function outside class from constructor
Jun 19, 2013 at 9:11pm UTC
I have the following class, I understand I can declare the constructor in the class and define it outside as a solution however I want to put it in the class and keep the class in my header. If I create the class object like:
Sales_data readtest(cin)
I want it to call my read function, however my read function isnt yet defined, if I define/declare it before my class, my read function takes a class member that is not yet defined creating a paradox (think im using the word corrctly lol)
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#ifndef MY_SALES_DATA_H
#define MY_SALES_DATA_H
#include <iostream>
#include <string>
using namespace std;
struct Sales_data{
//constructors
Sales_data() = default ;
Sales_data(const string& s, unsigned n, double d): bookNo(s), copiesSold(n), revenue(d*n){}
Sales_data(istream& in){read(in,*this );} //<--PROBLEM HERE
//members
string bookNo = "" ;
unsigned copiesSold = 0;
double revenue = 0.0;
//member default inline functions
Sales_data combine(const Sales_data &objectCombine);
string ISBN(){return bookNo;}
};
void read(istream& in, Sales_data &sdObject){
in >> sdObject.bookNo >> sdObject.copiesSold >> sdObject.revenue;
sdObject.revenue *= sdObject.copiesSold;
}
void add(Sales_data &objectAddTo, const Sales_data objectAddFrom){
objectAddTo.revenue += objectAddFrom.revenue;
}
void print(const Sales_data objectToDisplay){
cout << "Book Number: " << objectToDisplay.bookNo << endl
<< "Number Sold: " << objectToDisplay.copiesSold << endl
<< "Total Renvenue: " << objectToDisplay.revenue << endl;
}
//member function declared outside class.
Sales_data Sales_data::combine(const Sales_data &objectCombine){
revenue += objectCombine.revenue;
copiesSold += objectCombine.copiesSold;
return *this ;
}
#endif
Last edited on Jun 19, 2013 at 9:13pm UTC
Jun 19, 2013 at 9:26pm UTC
It is enought that you forward-declare the class before you declare the function.
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class Sales_data;
void read(istream& in, Sales_data &sdObject);
Jun 19, 2013 at 9:36pm UTC
You rock dude, I didnt know but should have known by common syntax that I could forward declare a class as well as a function.
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