[prog] Re: C++

[wolf]

well it now compiles but returns this error:
Compiling...
ld: Undefined symbols:
_main

shell returned 1

also does anyone know how and where in the program to tell it to write 
the information
to a file?

latest version :

#include <iostream>
#include <cstring>
#ifndef _CPP_OSTREAM
#define _CPP_OSTREAM	


using namespace std;

class cd {
	
private:
     string artist;
     string title;
     int year;
     string genre;
	
public:
	cd();	
	cd(string artist, string title, string genre, int year);
	//void showCD();
	//void saveCDLibrary();
	//void printCDLibrary();
	cd (string sartist, string stitle, string sgenre, int iyear) {
		// create a new cd object
		artist = sartist;
		title = stitle;
		genre = sgenre;
		year = iyear;
		
	}
};
	


cd::showCD() {
		// print a cd object
		cout << artist << " " << genre << " " << title << " " << year << endl;
	}
	
cd::saveCDLibrary(cd cdLibrary[], int length) {
		// need a fileIO stream of some sort.
		for (int i; i < length; i++) {
			cin << cdLibrary[i].showCD();
		}
	}
	
cd::printCDLibrary(cd cdLibrary[], int length) {
		// This maybe needs sorted...
		
		for (int i; i < length; i++) {
			cout << cdLibrary[i].showCD();
		}
	}
	
	void readCDLibrary(cd cdLibrary, int length) {
		string input, artist, title, genre;
		int year;
		
		// Open the file ?
		for (int i = 0; i < length; i++) {
			inputstream >> input;
			
			// artist, title, genre, year
			
			cdLibrary[i] = new cd(artist, title, genre, year);
		}
	}
	
	
	int main()
	{
		int CDcount = 0;
		const int LIBRARY_SIZE = 10;
		string artist, title, genre;
		int year;
		cd cdLibrary[LIBRARY_SIZE];
		
		// Ask if they want to read the CDs from a file or enter new
		// data:
		
		cout << "Read from file (1) or Enter new data (0)? ";
		cin >> ans;
		
		if (ans) {
			// read from the file?
			
			readCDLibrary(cdLibrary, LIBRARY_SIZE);
			
		} else {
			// read in information about CDs
			while (cdCount < LIBRARY_SIZE) {
				cout << "Enter CD Information:" << endl;
				cout << "Enter year: (0 to quit)";
				cin >> year;
				if (year == 0) { break; }
				cout << "Enter artist: ";
				cin >> artist;
				cout << "Enter title: ";
				cin >> title;
				cout << "Enter genre: ";
				cin >> genre;
				
				cdLibrary[cdCount] = new cd(artist, title, genre, year);
				cdCount++;
			}
		}
		
		saveCDLibrary(cdLibrary, LIBRARY_SIZE);
		printCDLibrary(cdLibrary, LIBRARY_SIZE);
		
	
		return 0;
	}
#endif

here is the original question I've been destroying : )
> write a simple program to track an individual's cd library, the
> program should permit the user to enter 10 cds. Each cd
> should contain the following items: artist, album title, year and
> genre. the program s! hould display all the cds in order
> by artist. design a class and represent each album as an object
> of that class. provide the capability to store the data
> in a text file and retrieve it again the next time the program is
>  run.

On Mar 14, 2004, at 12:12 PM, dominik.schramm at gmxpro.net wrote:

> Hi,
>
> wolf <wolf at wolfrising.net> writes:
>
>> [...]
>> here are the error messages:
>> Compiling...
>> cd.cpp:20: error: return type specification for constructor invalid
>
> The contructor must have an *empty* type specification, not "void".
> See below.
>
>> cd.cpp:29: error: `void cd::showCD()' and `void cd::showCD()' cannot 
>> be
>>     overloaded
>
> See below: the function signatures are the same (thus overloading is
> impossible) but the compiler sees this function twice, once in a 
> declaration,
> then in a declaration plus implementation.
>
>> cd.cpp:109: error: parse error at end of input
>
> Don't know about this. Maybe the missing semicolon? (see below)
>
>> this is line 20:
>> 20         void cd (string sartist, string stitle, string sgenre, int
>
> Leave away "void", should be:
>                   cd (string sartist, ...)
>
>> [...]
>> here's the current version of the program:
>> #include <iostream>
>> using namespace std;
>>
>> class cd {
>>
>> [...]
>> 	
>> private:
>>      cd(string artist, string title, string genre, int year);
>>      void showCD();
>
> This is the declaration for the showCD function.
>
>> [...]
>> 	void showCD() {
>>      // print a cd object
>>      cout << artist << " " << genre << " " << title << " " << year <<
>>      endl;
>> }
>
> This is another (!) declaration plus implementation of showCD. Since 
> the signature
> is the same in both cases, the compiler complains that you cannot do 
> overloading
> this way.
>
> BTW. It's confusing to implement member functions inside the class 
> declaration,
> I'd do this outside the class declaration, using names like cd::showCD 
> etc.
> I think the above error is an example of such confusion.
>
>> [...]
>> void readCDLibrary(cd cdLibrary, int length) {
>>      string input, artist, title, genre;
>>      int year;
>> 	
>>      // Open the file ?	
>>      for (int i = 0; i < length; i++) {
>>          inputstream >> input;
>> 		
>>          // artist, title, genre, year
>> 		
>>          cdLibrary[i] = new cd(artist, title, genre, year);
>>      }
>> }
>
> AFAIK there should be a ; after the class declaration.
>
>
> hope this helps,
> regards,
> dominik
>
> -- 
> Dominik Schramm <dominik.schramm at gmxpro.net>
> pgp key via http://www.cam.ac.uk.pgp.net/pgpnet/wwwkeys.html
>
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