C++ :: Defining Member Functions Outside Class Definition
Jan 3, 2014
#include "stdafx.h"
#include <iostream>
#include <math.h>
using namespace std;
class Calc {
[Code] ....
when i built it, it showed the following errors:
1>------ Build started: Project: rough, Configuration: Debug Win32 ------
1> rough.cpp
1>e:c programs
ough
ough
ough.cpp(17): error C3872: '0xa0': this character is not allowed in an identifier
1>e:c programs
The question is: Define the class Counter. An instance of this class is used to count things, but the counter should never be less than 0 (non negative number). The member variable should be private. I realize what I'm suppose to be using but can't implement the member functions needed..
int main(){ int value; cin >> value; Counter myCounter(value); for (int i = 1; i <= MAXLOOP; i++) { myCounter.increment();
"You cannot initialize the static data member in the class definition — that’s simply a blueprint for an object and initializing values for members are not allowed. You don’t want to initialize it in a constructor, because you want to increment it every time the constructor is called so the count of the number of objects created is accumulated."
Why don't you want to initialize it in a constructor?
Edit: Because every time it is called it will set it back to 0 or whatever the initializing value.
If you are doing some big program, usually, how do you organize the files? Put the class and its member in head file, but where to declare non member functions and where to define them? I don't want to put them all in one cpp file. If not, how to make them visible to the main cpp file?
Here is the assignment: (3pts) Given the following class header file, write the class’ source code for each of the accessor and mutator functions listed. (How the functions have listed their parameters, varying between passing by reference and by value.) Don’t forget to comment your code – it counts!
class Album { private: char * artist; // band or singer’s name char * title; // title of the album
[code]....
The input will be an array. My questions: First, am I on the right track?
When using (char * a) for a function, for example, this is passing the address of a, correct? so then *artist=a; changes what the address of a points to?
also, the functions are bool when I would expect void. Why? for all of the set_" " functions, the parameter is *... but for set_record_label it is *&. That appears to be a mistake to me. Is that right?
what is the difference between *& and * as parameters?
Suppose I make a class, something like having the constructor being invoked first makes sense, I don't have a problem with that. But, how could I limit access to functions until certain functions are called? Perhaps this isn't built into the language so you can't. And maybe this problem never comes up. For example if you have a set() and get() functions, if they are both public functions, there doesn't seem to be a way for the compiler at least now if set() never gets called you shouldn't call get(). I just see this as error prone if you need to use libraries, you have to know not to do it from documentation instead of something the compiler can check.
This week we are learning to use templates, and I don't understand how to call my member functions with my template based class. I tried the standard convention of calling member functions, but I keep getting an error saying name following"::" must be a class or namespace name. I'm thinking my problem lies with my typename T, but I am unsure. Line 16 is where I am getting tripped up.
#include "stdafx.h" #include <iostream> #include <string> using namespace std; template<class T> T Set { public:
I am supposed to implement the member functions of class Person.
class Person { public: Person(); Person(string pname, int page); void get_name() const; void get_age() const;
[Code] ....
The code I wrote is below. Where I am struggling is the program does not allow me to input age. Therefore, I cannot test if my temp for age works. It automatically defaults to 0 because it hasn't taken input. Here is my code:
// Program Title: Person function // Program Description: The program prompts the user for first and last name and age. // It then prints the output that was provided by the user.
#include<iostream> #include<string> using namespace std; class Person {
I am work on building a simple parse tree and the layout of my code look like this:
Headers pt_node.hiterator.hparsetree.h
Source files node.cppparsetree.cppmain.cpp
I am still relatively new to C++ , and have been advised to include function definition for the member function of both pt_node class and iterator class in the node.cpp file
I particular I have declare the following iterator.h:
Programe #1 // file.h class File { public: static const int var = 9; };
[Code]....
Program#1 is running fine, but program#2 gives linker error:
error LNK2005: "int GlobalVar" (?x@@3HA) already defined in file.obj
I know the header files are never compiled. Then in the above case, how the compiler knows the definition of variable var, but not able to find the definition of GlobalVar? What is the difference between this two programs?
I am looking at functions still and can't see the point in declaring the function at the top of the program, and then defining later i.e.
Code: #include <iostream> int add (int x, int y) { return x + y;
[Code] .....
I obviously don't have much real world experience with this and am interested to see where declaring and defining later would be useful and/or beneficial.
#include "IMyIntData.h" class MyIntData : public CPMUnknown<IMyIntData> {
I need to know what this syntax means (including MyIntData in angular brackets after parent class name) where IMyIntData is the Interface from where MyIntData is derived.
I have an abstract class called Mbase and from it derived two classes: Sparse and Dense. Now I have an array in which its elements can be either Sparse or Dense. So, I delcared the array to have pointers to Mbase class. For example:
PHP Code: Mbase** A; Sparse* A1 = new Sparse; Dense* A2 = new Dense; A[1] = dynamic_cast<Mbase*>(A1); A[2] = dynamic_cast<Mbase*>(A2);
Now, I have operator + defined in Sparse and Dense. but when I do
PHP Code:
A[1]+A[2]
I get that operator + is not defined for Mbase class. So, I tried to define it in the Mbase class
However, the last code does not compile complaining that it cannot declare a class of type abstract in Mbase operator +(Mbase A). I think this is because I am returning Mbase instance.
Write a class definition for a Fraction class. Its member fields are num and den, both of type int. The constructor builds the default fraction 1/1. It has the following operations:
void plusEquals(Fraction second); //Adds the second fraction to this fraction like the operator += void minusEquals (Fraction second); //Subtracts the second fraction from this fraction void timesEquals (Fraction second); //Divides this fraction by the second fraction void dividesEquals (Fraction second); // Divides this fraction by the second fraction void reduce(); // Reduces this fraction to lowest terms double todecimal(); //returns the decimal value of this fraction void scan(istream&); //scans a fraction written with a slash as in ¾ void print(ostream&); //prints a fraction using a slash Fraction(); //constructs a default fraction with denominator 1, numerator 0 Fraction(int n, int d); //constructs a fraction given value for num and den
2. Write a menu-driven driver program designed to allow thorough testing of your Fraction class.
I am currently stuck on what I should do next in a program I am working on. These are my instructions:
Design, implement, and test a class for storing integer arrays "safely". The array should be able to hold any number of integers up to 100.
In the class header file "SafeArray.h" students must define the class and specify the constructor/destructor functions, the public methods and private variables. In the class implementation file "SafeArray.cpp" students must implement the following operations:
constructor - to initialize the object. copy constructor - to copy an object. destructor - to delete the object. set - allow the user to set a value of the array at a particular location. get - allow the user to get a value of the array at a particular location. print - print out the array. add - add the elements of one array to another. subtract - subtract the elements of one array from another.
The output of my program is suppose to look like this:
Set q1: 2, 3, 4 Print q1: 2, 3, 4
Set q2: 1, 4, -2 Print q2: 1, 4, -2
Add q2 to q1
Print q1: 3, 7, 2 Get q1 at 1: 7
Here is the code I have so far.
*main.cpp*
#include <iostream> #include "SafeArray.h" using namespace std; int main() {
I found way around this, but I would like to know why it shows multiple declarations.
My solution is to declare this class in function body(void LoadLevel()), just before the throw statement. But why can't I define it inside my namespace, but outside function?
vijay13@ubuntu:~/Downloads$ g++ -o test test.cpp -I /home/vijay13/Downloads/OGDF-snapshot/include/
I am getting following error:
vijay13@ubuntu:~/Downloads$ g++ -o test test.cpp -I /home/vijay13/Downloads/OGDF-snapshot/include/ /tmp/ccPE8nCu.o: In function `main': test.cpp:(.text+0x26): undefined reference to `ogdf::Graph::Graph()' ...................... so on
I changed the name of my Invoice class to 'Application' and then it generated errors such as follows
Error9'Invoice.Invoice' does not contain a definition for 'Documents' and no extension method 'Documents' accepting a first argument of type 'Invoice.Invoice' could be found (are you missing a using directive or an assembly reference?)c:userskeildocumentsvisual studio 2013projectsinvoiceinvoicewritefile.cs1840Invoice
Error3'Invoice.Invoice' does not contain a definition for 'Run'C:UsersKeilDocumentsVisual Studio 2013ProjectsInvoiceInvoiceProgram.cs1921Invoice
I have added my classes here, lso I have added the sln to this post.
using System; using System.Collections.Generic; using System.ComponentModel;
I am unable to understand how a move constructor works in this example of code. If someone could break down the process of what is taking place and explain to me on why to use a move constructor.
Code: class MyString { MyString(MyString&& MoveSource) { if( MoveSource.Buffer != NULL ) { Buffer = MoveSource.Buffer; // take ownership i.e. 'move' MoveSource.Buffer = NULL; // set the move source to NULL i.e. free it } } };
Example from "SamsTeachYourself: C++ in One Hour a Day"
