I made a program and when I try to use the main driver to instantiate everything it says invalid storage class for a function. All of my code is in 4 separate files i'm just trying to get it to run now.
I am porting code from windows using visual studio to mac with xcode.
Quite a lot of issue have a appeared, which is no surprise, one warning that keeps on appearing is Explicit Specialiszation cannot have a storage class:
i want to modify value of whole array by passing it to a function and make each value of array multiplied by 3 ,return the value to main and print it using pointer.
error : invalid Lvalue is the error
Code:
#include<stdio.h> main() { int i,arr[10]; for (i=0;i<=9;i++) { printf("Enter value of arr[%d] : ",i); scanf("%d",&arr[i]);
I have this piece of code from the book "Modern C++ Design" that checks for compile-time error. When i tried to compile it, i get the error "invalid application of size of to function type". How to make this compiler-time checker work?
I have a class that I'm going to use to store a category. Right now there are seven options, but there is the potential for a whole lot more in the future. So I started off by storing an integer as the private member. I then used static constants to define the numeric values to represent each category, then a set of static constant strings that corresponds to those numbers in case I need their actual names. Finally I set up some static functions to convert between the integer value and the string, and vice versa.
I'm not sure if this is the best way to go about this. For one it makes the categories names and designations unchangeable. I thought that storing them in a file would be a better option, but then i needed a container that is the equivalent of a constant.
I thought of defining a class to contain an int and the associated string. It would be designed so that it can only be initialized with both items. Then provide no functionality to change the contents. So I've basically created my own constant.
decalration won't allocate storage, while definition will. This is a test program:
#include <iostream> using namespace std; extern int ei; int i;
[Code].....
Others are all fine in this program except ei. compiler error: undefined reference to ei.
I understand ei is only declared so there is no memory address, but when I do ei=1, then ei completed it's definition, why still cannot use pei to get it's address?
So the RPG I have been making is based on this tutorial URL.....I don't entirely understand how the Item storage system is supposed to work. It looks like the array shown is for one item but, there are 3 lines of code that correlate. The author says that this is a repeatable bit of code for each item so.... i'm just completely lost. The player will have two or three to start and there are 4 battle/health items and one key ....
where to start and how it should be structured. how I should go about writing this program, like should i make functions, pointers, etc. And to display the menu, is it easiest to just use printf statements or is there something more efficient.
Say in my main class, I have a function fight(Player p1, Player p2) and I would like to do something like this in the fight function, given that p1 is the human and p2 is the computer:
//function fight() fight(Player p1, Player p2) { p1.func2(); } //using function fight() fight(human, computer);
When I compile the program, I got this: error: ‘class Player’ has no member named 'func2()' What can I do to allow p1 to call func2 inside fight()? I'm not allowed to use pointers as the parameter for fight() and have to use the signature fight(Player p1, Player p2).
So I have a base class, lets call it base. In base I have a virtual function called update(), update just couts "base" then I have a class derived from base called derived;
it has a function called update(), update just couts "derived" then I create a vector called Vec it's initialised like this:
std::vector<base> Vec;
then I add an element into it like this
Derived DerElement; Vec.push_back(DerElement);
then when I type:
for (int i=0; i<Vec.size(); i++) { Vec.at(i).Update(); }
It outputs:
Derived DerElement2; DerElement2.Update();
and it outputs this:
#include <iostream> #include <vector> class Base { public: virtual void Update() {
I am writing a program which is using SDL library. I have two different classes which one of them is Timer Class and the other is EventHandling Class.
I need to use some member functions and variables of Timer in some Eventhandling Class member functions, Although I want to define an object of Timer in int main {} and relate it to its member function that has been used in Eventhandling member function in order that it becomes easier to handle it, I mean that I want to have for example two objects of timer and two objects of Eventhandling class for two different users.
I do not know how to relate an object of a class from int main{} to its member function which is being used in another class member function.
I just wondering if a base class can call the overridden function from a Derived class?
Here's an example:
//Base Class H class BaseClass { public: BaseClass(); virtual ~BaseClass(); virtual void functionA();
[Code] ....
So basically, when I am creating a new object of Derived class, it will initialize BaseClass and the BaseClass will call functionA but I want it to call the function overridden by Derived class.
I know that if I call newObj->functionA it will call the overridden function. Right now I want the base class to call the overridden function "this->functionA(); in BaseClass" during its initialization. Is it possible to do that?
I'm trying to write a simple Delegate class with a Bind() and Invoke() function. For now it only needs to support a void class function with no parameters. I've searched around and found quite a few exmaples, though, those class are heavily templated and I lose track trying to simplify it.
So far my code is following:
Code: #include <windows.h> class Test { public: void DoSomething() { MessageBox(NULL, L"Test::DoSomething!", NULL, 0);
[Code] ....
The part I am having difficulty with is assigning &Test::DoSomething to the m_Callback variable.
&tObject::DoSomething works, yet _Callback which I pass &Test::DoSomething to does not work.
I am facing a real-life problem, it can be simplified as below:
#include <iostream> using namespace std; class B; class A { public: void f1(A a) {} void f2(B b) {}
[Code]...
There is no problem at all with the f1(), it compiles and executes without any problem. But f2() gives compilation error. How to solve this?
The error message is: error: 'b' has incomplete type This is just to define the function f2() in a class, that uses an instance of its child class as one of its arguments.
Basically, I have a base class called MainShop and it has 3 derived classes which are SwordShop, SpellBookShop and BowShop. I want the base class to be able to call a function from one of the derived classes but no matter what i do, it doesn't seem to work!
I have two other derived classes, but its basically the same concept. I have a function in one of the derived classes and i would like to call it from the base class. This is one my derived classes:
I am currently having an issue with a piece of code that I am writing in which I need to use a vector of a child class as a parameter in a function in the parent class. Below is an example of my code:
#include "child.h" #include <vector> class parent { parent(); function(std::vector<child> children); // rest of class here }
When I do this my program doesn't compile. However if I try to forward declare, as shown in the following example, it once again refuses to compile:
#include <vector> class child; class parent{ parent(); function(std::vector<child> children); // rest of class here }
This time, it refuses to compile because it needs to know the full size of the class child in order to create the vector. How to being able to access the child is essential for my program, so what should I do?