I am experimenting with the c++11 regex and came across an item missing from my limited c++ knowledge.
From this article: [URL] ....
I am unfamiliar with this function with the -> operator?
Code:
auto begin(strip const & s) -> char const *
{
return s.first;
}
Is this code the same?
Code:
char const* begin (strip const& s) {
return s.first;
}
What is the difference between:
const int testFunction() &
int testFunction() const
The Light and Fan are two different vendor classes and they are not derived from any base class. I am trying to implement the Command design pattern but with generic implementation, so it should work in future with any new vendor class like Door, Window etc without much change in client code. I have thought about a Factory method but it will not work because it needs a Base class. I am trying to learn the design patterns.
Light *myobj;
Fan *myobj;
int choice;
cout<<"Select Light (1): ";
cout<<"Select Fan (2): ";
[Code] ....
Error:conflicting declaration 'Fan*myobj'
It shows too many type declaration in the void push function. And I use turbo c++..
#include<stdio.h>
#define size 5
struct tack {
int top;
int item [10];
} void push(struct tack *s, int data)
[Code] .....
Here's my program: - Program which inputs a string from user, reverses it and displays it.
#include <iostream>
using namespace std;
void string_reverse (char [], const int);
int main() {
const int arraysize = 10;
char string[arraysize];
[Code] ....
In the string_reverse function, I have declared temp character type array but on line 38, the
compiler is throwing 3 errors: -
error C2057: expected constant expression
error C2466: cannot allocate an array of constant size 0
error C2133: 'temp' : unknown size
I have declared a constant integer arraysize in line 35. Now I have no clue why is this happening because I think as I have declared it as a constant integer variable, this should not happen.
I wrote this program and compiled in turboc, but it gets error"declaration syntax error" .
Code:
#include <stdio.h>
int main()
int isprime(int n)
{
if(n<2)
return 0;
[Code] ....
I am just learning using class template but I keep getting error unable to match function definition to an existing declaration
template <typename T>
class Homework {
private:
string name;
public:
template <typename T>
void SetName(T val);
[Code] ....
I've written the following code and keep getting the errors:
Error1error C2244: 'Supermarket<temp>::operator =' : unable to match function definition to an existing declaration
Error2error C2244: 'Supermarket<temp>::setName' : unable to match function definition to an existing declaration
Error3error C2244: 'Supermarket<temp>::setArea' : unable to match function definition to an existing declaration
#ifndef SUPERMARKET_H
#define SUPERMARKET_H
#include<string>
#include<iostream>
using namespace std;
[Code] .....
I moved the files to the .h file, and now I'm getting
Error2error LNK1120: 1 unresolved externals
I searched the web for error: C3867... and the discussions where murky or obscure.
My code excerpt is:
#pragma once
#include <windows.h>
#include <stdlib.h>
#include <process.h>
void PutUpfrmIO(void *);
namespace WordParsor {
[Code] .....
I get the generic message:
error C3867: 'WordParsor::Form1::PutUpfrmIO': function call missing argument list; use '&WordParsor::Form1::PutUpfrmIO' to create a pointer to memberc:userskingc++wordparsorwordparsorForm1.h... and the suggestion fix generate another error.
One person suggested the gcroot<> object wrapper... but I do not know how to modify/declair the function or its argument type.
I am trying to make a menu program and was wondering if there is a way to declare something more than once without using a different word.
ex.
#include <iostream>
using namespace std;
double grams, ounces, inches, feet, meters; //units to convert
int choice; //menu choice
int main() {
cout << "Welcome to Measurement Converter" << endl;
[Code] .....
I dont really know how to explain it but im trying to use int choice to make choose a program from a simple list.
I would like to know the difference between the following two forms of array declaration:
(1)double myArray[3] = {1.0, 2.0, 3.0};
(2)array<double,3> myArray = {1.0, 2.0, 3.0};
If I say the second one allows to use different functions like .begin(), am I right? Is there any other difference between these two declaration?
Can we use using declaration within name space scope? is it safe to use it?
I think we can use using declaration for class scope and function scope only.
I am trying to understand the behavior of following code. Basically how does printf() prints the value rather than address.
Does initializing value to a pointer during declaration makes a difference when assigned from a variable?
Code:
1 #include <stdio.h>
2
3 int main() {
4 const char *var1 = 'A';
5 int *vint = 10;
[Code] ....
I read that Memory is allocated during definition of a variable and not during declaration. Declaration is something like,
Code: int x;
And definition is assigning some value to it. This is what my professor taught. My doubt is if memory is not allocated during declaration, then how the compiler successfully compiles and runs the following, which i had already tried.
Code:
#include<stdio.h>
#include<conio.h>
int main() {
int c;
int *p=&c;
printf("%x",p);
getch();
return 0;
}
The variable c is only declared. But the program outputs a memory address. Shouldn't it show an error?
I've included <cstddef> into a project of mine in favour of <stddef.h>. When I tried to compile my project, I get 50+ errors stating that types such as "::size_t", "::div_t" and "::abort( )" have not been declared even though <cstddef> includes <stddef.h>.
I've tried searching both the global namespace and the standard namespace, but neither way works. At this moment in time, I don't have any compiler options enabled that may affect the way identifiers are defined, C++11 isn't enabled (which doesn't affect the <cstddef> header anyway), the project is a C++ project, and I've tried using the plain old <stddef.h> header, but the problems still persist.
I'm using GNU's C++ compiler ("__GNUG__" is defined).
I have recently found this article: URL.....In their example, by declaring variables in other order, they saved 8 bytes. However, shouldn't compiler take care of it? Is it true, and should I declare variables more carefully?
View 3 Replies View RelatedIf i declare 2 variables like this static int first, second; will both of them be declared static or will only first be declared static and second a regular variable?
View 5 Replies View RelatedI've got some problems with the declaration of a bitset container in my class
I've got a class A and want to have a bitset container in it, whose size just get's defined when running an instance of this class:
#include <bitset>
class A {
bitset <n> bc;
A(int n) : n(n) {};
};
Something like that.
I want to understand the ways in which arrays can be declared and used. What each of the following do or what's the difference between them and what would be the length of each:-
1 - char ary1[50];
2 - char ary2[50] = {'H','e','l','l','o'};
3 - char ary3[50] = {'H','e','l','l','o',' '};
4 - char ary4[50] = {' '};
5 - char ary5[50] = {' ','H','e','l','l','o'};
6 - char ary6[50] = {' ','H','e','l','l','o',' '};
#include<iostream>
#include<conio.h>
#include<string>
using namespace std;
class ir;
class Bank_acc {
private:
string name,type,s;
long int accno,temp,balance,in;
[Code]....
errors are:
|6|error: forward declaration of 'class ir'|
|54|error: invalid use of incomplete type 'class ir'|
|99|error: no matching function for call to 'ir::interest()'|
Code:
struct foo {
char label[64];
int state;
} bar[3] = { };
Will the above code ALWAYS initialize to 0 all objects:
bar[0].label
bar[0].state
bar[1].label
bar[1].state
bar[2].label
bar[2].state
Using gcc and g++, it does in my testing But was wondering if it can be unsafe under some circumstances.
I even tried without = { } and it is still initialized to 0 for all objects!
I want to access the body of the Add() of a list in c# to see how it works, but it only just gives me the declaration.
[DebuggerTypeProxy(typeof (Mscorlib_CollectionDebugView<>))]
[DebuggerDisplay("Count = {Count}")]
[Serializable]
public class List<T> : IList<T>, ICollection<T>, IList, ICollection, IReadOnlyList<T>, IReadOnlyCollection<T>, IEnumerable<T>, IEnumerable {
public void Add(T item); // thats all. I tried go to declaration but still gives me this line of code. This is from metadata in Visual studio.
}
How this thing work. It just a declaration not a definition yet its still doing something. How is that possible.
I have a class "SelectionGroup" which derives from a class "RMFObjectContainer". RMFObjectContainer has member variables of type SelectionGroup, so I need to include SelectionGroup.h in the header of RMFObjectContainer.h.
However, since SelectionGroup needs RMFObjectContainer to derive from it, I get a typical case of mutual inclusion.
I then proceeded to put the forward declaration
class RMFObjectContainer;
instead of
#include "RMFObjectContainer.h"
into the header of SelectionGroup.h.
However, I receive the following compile error (MSVC2010), as if the forward declaration was unseen:
#pragma once
#include "Solid.h"
#include "Entity.h"
#include "SelectionGroup.h"
[Code]....
is possible to combine structures declaration and definition in programming language?
View 3 Replies View RelatedAny difference between
Code:
class SomeOtherClass;
void foo(SomeOtherClass* p);
And
Code:
void foo(class SomeOtherClass* p);
I was told that "2" would limit the scope of the forward declaration to the declaration of foo... However, after testing it, it appears that both behave the same...
I keep getting a "Declaration syntax error" at line ""int main()". Is there something wrong with my int main()? And how do I go about it? Here is the program:
#include<stdlib.h>
#include<iostream.h>
#include<stdio.h>
#include<math.h>
#include<conio.h>
float rung4(float x, float y, float h)
int main() {
float eps=0.00001;
[Code] .....