Trouble creating classes

Question

adaniel058 0 Newbie Poster

16 Years Ago

I have tried to create a simple class where the program passes a name and telephone number to my class type and then prints it to the screen. It tells me I have undeclared identifiers, but I am constructing my program just like an example we did in class. Can someone tell me what I am doing wrong?!

// Specification file (Time.h)
// This file gives the specification
//of a phone abstract data type

#include <iostream>
#include <string>

class Phone
{
public:
	void Set(string firstName, string lastName, int number);

	void Write() const;

	Phone(string initfName, string initlName, int initNum);

	Phone();

private:
	string fName;
	string lName;
	int Num;

};

//Implementation file (phone.cpp)

#include "Phone.h"
#include <iostream>
#include <string>

using namespace std;

void Phone::Set(string firstName, string lastName, int number)
{
	fName = firstName;
	lName = lastName;
	Num = number;
}

void Phone::Write() const
{
	cout << fName;
	cout << lName << endl;
	cout << Num;
}

Phone::Phone(string initfName, string initlName, int initNum)
{
	fName = initfName;
	lName = initlName;
	Num = initNum;
}

Phone::Phone()
{
	fName = "";
	lName = "";
	Num = 0;
}


#include "Phone.h"
#include <iostream>
#include <cctype>
#include <string>

using namespace std;

int main()
{
	Phone thePhone(Andrew, Daniel, 4906996);
	thePhone.write();
	cout << endl << endl;
	system("pause");
	return 0;
}

c++ object-oriented-programming

Edited 16 Years Ago by adaniel058 because: n/a

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Latest Post 16 Years Ago Latest Post by adaniel058

Dani AI

Generated 9 Months Ago

Good troubleshooting so far by and — the three problems that appeared here are very common and explain the compiler messages.

First, a missing semicolon after a class declaration will make the compiler treat subsequent tokens (including standard headers) as part of the class and produce baffling errors like the C2143 you saw. The C++ grammar requires that class/struct/union declarations end with a semicolon; fixing that single typo usually clears the cascade of errors. See the language rules for classes here: class (cppreference).

Second, never rely on putting using namespace std; into a header. That can silently change name lookup for every translation unit that includes the header and is considered bad practice; prefer fully qualified names in headers (or minimal using-declarations scoped in source files). The namespace page explains the risks and mechanics: namespaces (cppreference). Related: the enum you added is fine, but prefer declaring it straightforwardly (no need to prepend :: inside the same header) — see enum (cppreference).

Third, when calling constructors or functions, string literals must be quoted; otherwise the compiler treats them as identifiers. After those fixes, also match declarations and definitions exactly (case-sensitive names and parameter types).

A few further tips not shown in the thread: prefer const std::string& parameters to avoid unnecessary copies; use constructor initializer lists for member initialization; add include guards or #pragma once to headers; store phone numbers as strings (to preserve leading zeroes, formatting and non-numeric characters); avoid non-portable calls like system("pause") in production code. For std::string details, refer to basic_string (cppreference).

Turning on all compiler warnings and building after each small change makes these kinds of mistakes obvious fast.

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Ancient Dragon 5,243 Achieved Level 70

16 Years Ago

Inside the header file you have to tell the compiler that string is in std namespace. Putting using namespace std; in the *.cpp files is not sufficient because that line is located after the header file that contains the Phone class.

class Phone
{
public:
	void Set(std::string firstName, std::string lastName, int number);

	void Write() const;

	Phone(std::string initfName, std::string initlName, int initNum);

	Phone();

private:
	std::string fName;
	std::string lName;
	int Num;

};

Edited 16 Years Ago by Ancient Dragon because: n/a

Ancient Dragon 5,243 Achieved Level 70

16 Years Ago

line 72: Andrew and Daniel are assumed to be variable names because they are not enclosed in double quotes.

Edited 16 Years Ago by Ancient Dragon because: n/a

Fbody 682 Posting Maven

16 Years Ago

Generally, I wouldn't be this blatant, but I think it warranted this time.

Look at Line 72, the first line of your main().

Phone thePhone(Andrew, Daniel, 4906996);

You are trying to send Andrew and Daniel to the function. The problem is that C++ sees them as undeclared variable names. It appears that what you actually want are string literals. To create a string literal, place the information in "double-quotes".

Phone thePhone("Andrew", "Daniel", 4906996);

In this example, "Andrew" and "Daniel" are now string literals, not variable names.

EDIT:
Oops, where'd AD's reply come from???? I reloaded before I posted to be sure...

Edited 16 Years Ago by Fbody because: n/a

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adaniel058 0 Newbie Poster · Answer 1 · 2010-07-21T00:56:00+00:00

Thanks so much for your help! Doing that I can almost get it to work!
Now when I try to pass arguments to the functions in my class it tells me my arguments are undeclared identifiers. I assume this means I have an error somewhere in my declarations but I cant seem to figure it out. This is my first program using classes so any help would be great!

I feel like Im making this harder than it is or should be....

// Specification file (Phone.h)
// This file gives the specification
//of a phone abstract data type


#include <string>

class Phone
{
public:
	void Set(std::string firstName, std::string lastName, int number);

	void Write() const;

	Phone(std::string initfName, std::string initlName, int initNum);

	Phone();

private:
	std::string fName;
	std::string lName;
	int Num;
};

//Implementation file (phone.cpp)

#include "Phone.h"
#include <iostream>
#include <string>

using namespace std;

void Phone::Set(string firstName, string lastName, int number)
{
	fName = firstName;
	lName = lastName;
	Num = number;
}

void Phone::Write()
{
	cout << fName;
	cout << lName << endl;
	cout << Num;
}

Phone::Phone(string initfName, string initlName, int initNum)
{
	fName = initfName;
	lName = initlName;
	Num = initNum;
}

Phone::Phone()
{
	fName = "";
	lName = "";
	Num = 0;
}

// Program file

#include "Phone.h"
#include <iostream>
#include <cctype>
#include <string>

using namespace std;

int main()
{
	Phone thePhone(Andrew, Daniel, 4906996);
	thePhone.Write();
	cout << endl << endl;
	system("pause");
	return 0;
}

Ancient Dragon 5,243 Achieved Level 70 Team Colleague Featured Poster · Answer 2 · 2010-07-21T01:40:00+00:00

>>Oops, where'd AD's reply come from???? I reloaded before I posted to be sure...
That happens to us all -- no problem.

adaniel058 0 Newbie Poster · Answer 3 · 2010-07-21T02:21:22+00:00

Well I fell like a moron. I got so wrapped up in thinking it had to be something hard I never even realized I was not passing my arguments properly. Thank you both so much

adaniel058 0 Newbie Poster · Answer 4 · 2010-07-21T08:07:00+00:00

One more quick question. Im getting syntax errors now that Ive created an enum data type in my header file. Any thoughts?

1>c:\program files\microsoft visual studio 9.0\vc\include\cctype(19) : error C2143: syntax error : missing ';' before 'namespace'

1>c:\users\andrew\documents\visual studio 2008\projects\phonebook\phonebook\phone.cpp(6) : error C2143: syntax error : missing ';' before 'using'

Appears to be in my .cpp file.

// Specification file (Phone.h)
// This file gives the specification
// of a phone abstract data type
// pg 551

#include <string>

enum phoneType {Home, Office, Fax, Cell, Pager};

class Phone
{
public:
	void Set(std::string firstName, std::string lastName, int number, ::phoneType newType);

	void Write() const;

	Phone(std::string initfName, std::string initlName, int initNum, ::phoneType initType);

	Phone();

private:
	std::string fName;
	std::string lName;
	int Num;
	::phoneType type;
}

//Implementation file (phone.cpp)

#include "Phone.h"
#include <string>

using namespace std;

void Phone::Set(string firstName, string lastName, int number, phoneType newType)
{
	fName = firstName;
	lName = lastName;
	Num = number;
	type = newType;
}

void Phone::Write() const
{
	cout << fName << " ";
	cout << lName << endl;
	cout << Num;
}

Phone::Phone(string initfName, string initlName, int initNum, phoneType initType)
{
	fName = initfName;
	lName = initlName;
	Num = initNum;
	type = initType;
}

Phone::Phone()
{
	fName = "";
	lName = "";
	Num = 0;
	type = Home;
}

Fbody 682 Posting Maven Featured Poster · Answer 5 · 2010-07-21T18:32:11+00:00

This is your problem:

class Phone
{
public:
	void Set(std::string firstName, std::string lastName, int number, ::phoneType newType);
 
	void Write() const;
 
	Phone(std::string initfName, std::string initlName, int initNum, ::phoneType initType);
 
	Phone();
 
private:
	std::string fName;
	std::string lName;
	int Num;
	::phoneType type;
} //<----there is something missing here.....

adaniel058 0 Newbie Poster · Answer 6 · 2010-07-21T19:37:19+00:00

Thankfully I figured that out without too much trial and tribulation last night. I get so frustrated I miss the little things. Thank you Fbody

Trouble creating classes

Dani AI

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