C++ ::  Why Every First Function Of Each File Get Error - Multiple Definition Of Void Pointer

May 6, 2014

I declared all functions in header file, such as:

bool readCase();

bool meshing();
bool readMesh();

bool calculateFlowfield();
bool readFlowfield();

bool calculateEvaporation();

And then I define them in separated .cpp files, each .cpp file include the header, but I got multiple definition error, why?

Even the int main() function, which only decalred and defined once got this error, why?

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C++ ::  Multiple Files Causes (Multiple Definition) Error?

Jul 15, 2013

I'm using multiple C++ files in one project for the first time. Both have need to include a protected (#ifndef) header file. However, when I do that, I get a multiple definition error.

From what I found from research, adding the word inline before the function fixes the error. Is this the right way to do this, and why does it work? Should I make a habbit of just declaring any function that might be used in two .cpp files as inline?

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C/C++ :: Getting Rid Of Multiple Definition Error

Dec 9, 2014

how to get this bug to go away and I am stressing about it. The project im working on simulates packet sending and receiving along with ROT13 encryption of the packets. The error lies within the .cpp file anywhere that I used IPHost.

header file

#ifndef IPHOST_H
#define IPHOST_H
#include <string>
#include <iostream>
class IPHost {
public:
//Default constructor defaults to 0.0.0.0

[code]...

error message:

In function 'ZStorSt13_Ios_OpenmodeS_':
line 11: multiple definition of 'IPHost::IPHost()'
line 11: first defined here

**this error repeats for every line in the .cpp in which IPHost is used.

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C/C++ :: GCC Compiler Does Not Detect Multiple Definition Error

Oct 31, 2012

I am trying to compile the files file1.c and file2.c using Mingw (gcc)

/////////////////////
header.h
////////////////////
#ifndef header
#define header  
int variable;  
#endif

[Code] ....

I would have expected a multiple defnition error when linking the two .c files. as in both the files, with the 'int variable' command, the variable 'variable' is defined (memory allocated) and during linking the linker doesnot know which variable to link to.

I get an error though when i use "int variable =123;" in the header file instead of the "int variable;" statement. i dont understand as in both the cases the variable is defined (memory is allocated) and the linker should give a multiple definition error.

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C++ :: Cannot Cast From Void Pointer - Returns Always Error C2440

Apr 25, 2013

I having a problem which I'm not able to resovle. I try to dereference a void pointer but I always get a C2440 error. It says: 'static_cast':void* cannot be converted in wqueue<T>. I tried different cast ways but I always get the same error. As far as I found out I should get the error if I try to dereference without cast but in my case I cast before and still get that error.

void *srumbler (void *arg) {
wqueue<workclas*> m_queue= static_cast<wqueue<workclass*>>(arg);
return NULL;
}

The according type wqueue in the header file:

template <typename T> class wqueue {
list<T> m_queue;
pthread_mutex_t m_mutex;
pthread_cond_t m_condv;

[Code] .....

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C++ :: Void Pointer Argument In A Function?

Jun 11, 2014

Why does the following code compile and execute without any error? I mean, the function compareid should get 2 arguments so why does the compiler not complaining, is it because of the type of arguments?

Code:
#include <stdio.h>
int compareid(void* info, int value); // ansi declaration
int compareid(void* info, int value)

[Code] .....

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C++ :: Return Struct Pointer From A Void Function And Print

Mar 17, 2013

i need to return a struct pointer dynamically allocated inside a function call void function() which is done using 'out parameters' in following code

struct my_struct {
int x;
} void my_function( my_struct** result ) {
my_struct* x = new my_struct{ 10 };
//...
*result = x;
}

Now i have a doubt, so if i want to print the return value from struct pointer, should i need to print it in the void function() or in the caller the function...

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C++ :: Multiple Definition Of Class?

Nov 18, 2013

I have a question about multiple definition of class LoaderException.

I have such code:

LevelLoader.hpp
#ifndef LEVELLOADER_HPP
#define LEVELLOADER_HPP

[Code]....

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?

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C++ :: How To Call A Function With Multiple Pointer Arguments

Nov 3, 2013

In my code, I have a function like such: int function1(int* a, int* b). I am wondering how to call it in int main.

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C++ :: How To Convert Void Pointer To Int / Double / String Pointer

Mar 7, 2013

I have a function:

const void insertStuff(const void *key, const int value){
// I want to convert the void pointer into one
// of three types of pointers(int, string, or double)
switch(value){
case 0:
int *intPtr = key;

[Code] .....

But this causes an error of: "crosses initialization of int*intPtr"

What's the correct way of implementing this?

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C++ :: Opening A File In Void Function

Feb 26, 2013

how do you open a file inside of a void function

this is the code i have

#include <iostream>
#include <fstream>
#include <sstream>

[Code]....

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C++ :: How To Output Void Function On A Text File

Feb 12, 2013

So I am writing this code that analyzes a file called "analysis.txt" and prints out in an ouput file (called "report.txt") the results of the analysis, i.e.,(the frequency of all alphabet letters present in the file).

I am having trouble with outputing on the file2.

here is what I have:

Code:

#include<iostream>
#include<fstream>
using namespace std;
ifstream file1;

[Code]....

I tried to lose the "<<" after the file 2, but it's still giving me an error. how to output a void function on a text file?

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C++ :: Inputting TXT File Into 2 Parallel Arrays Via Void Function

Nov 10, 2014

I have a .txt file that I need to input into two parallel arrays. The first array needs to be on dimension and the second needs to be two dimensions.

This is a sample from the .txt file:

Australia62.762.163.359.7
Austria052.853.154.6
Belgium30.430.327.525.3
Canada61.356.257.754.5
Chile026.425.431.1
CzechRepublic038.327.325.2
Denmark65.067.162.355.0
Estonia51.732.929.834.3
Finland55.242.942.143.3
France35.728.330.228.8
Germany56.447.242.646.6
Greece30.326.925.013.1
Hungary032.521.818.6
Iceland068.271.666.0

this is what I have for code so far:

#include <iostream>
#include <fstream>
#include <string>
#include <iomanip>

using namespace std;
const int SIZE = 40;
const int COLUMN = 5;
void getData(ifstream& inf, string n[], double tstData[][COLUMN], int count);

[Code] .....

when I compile and run the code and have it display it does not read the first item into the 1-d array, instead it appears to read the 4th number from the left into the 1-d array and then into the second spot in the 2-d array, then again in its proper place and finally it has this number repeating through the rest of the arrays:

-92559631349317830000000000000000000000000000000000000000000.00 followed by the number 59.7 from the .txt and the long number again.

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C++ :: Template Definition Error

Apr 16, 2013

I have an issue converting VC++6 code to VC++ 2010. The following template function definition is not allowed by the new compiler:

template <> void AFXAPI DelElems <CBrush*> ( CPen** objects, int count ) {
for ( int i = 0; i < count; i++, objects++ )
if (*objects)
delete *objects;
}

All errors refer to the header of the template function:

- syntax error : '<'
- syntax error : missing ';' before '<'
- 'DelElems' : illegal use of type 'void'
- unrecognizable template declaration/definition

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C/C++ :: Pointer To A Function Used In Arithmetic Error

Nov 23, 2014

I'm working on a short program to calculate the mode of a vector of ints. I am new, so not extremely familiar with pointers, and passing items to functions. This is something I've struggled with (obviously, or I wouldn't be here). I am currently getting the following error when I try to compile this program using g++:

warning: pointer to a function used in arithmetic

I receive this error for the following lines: 66, 73, 75, 81.

I am not using pointers here so I do not understand why this error crops up, much less how to fix it. Here is the code I am struggling with:

#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <limits>
using namespace std;
vector<int> getModes(vector<int> userValues);

[Code] ....

The errors are on lines 54, 61, 63, and 69

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C++ :: Class Calendar - Pointer To A Function Error

Nov 30, 2013

I have a class Calendar which has an attribute of priority queue, that accepts records of structure defined as:

typedef void (Calendar::*eventPointer)();
struct activationRecord {
double Time;
int Priority;
eventPointer activationEvent;
};

And here is the problem. Whole day I've been trying to fill the Calendar with some test entries by calling the method

void Calendar::calendarPush(double Time, int Priority, eventPointer event)

This is how I call it

calendar.calendarPush(Time, Priority, &Calendar::calendarEmpty);

But Visual Studio keeps to warn me with this error

argument of type "bool (Calendar::*)()" is incompatible with parameter of type "eventPointer *"

#include <iostream>
#include "Calendar.h"
using namespace std;
int main() {
cout << "Initializing ..." << endl;
double Time = 0.0;
int Priority = 0;

[Code] ....

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C++ :: Error Using (this) Pointer In Static Members Function?

Sep 4, 2012

I am trying to use 'this' pointer but i am confused why 'this' pointer is not available for static member functions.

Code:
#include <iostream>
#include <fstream>
#include <stdlib.h>
using namespace std;
const int MAX = 20;
const int MAXPTR = 100;
class name {
private :
char fname[MAX], mname[MAX], lname[MAX];

[code].....

I am using GNU GCC Compiler via Code::Block

Error : 'this' is unavailable for static member functions

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C :: Void Functions With If Else Construct Not Printing Multiple Lines

Apr 12, 2014

This code i made is a cent converter from 5 to 95 cents. The problem i'm receiving is when the 'cents' function is sent back to the 'main' function it only prints one line. It seems to just print the first if construct that complies with the statement. Is there anyway i can have this function print multiple cent values? For example if 60 cents was entered it would only print '50c', and i want it to print '50c' and '10c' instead.

Code:

#include <stdio.h>
int x;
void check(int x)
{
if( x < 5)
printf("Less then 5 cannot be calculated
");
else if(x > 95)

[code]....

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C :: Dereferencing Of Void Pointer

Apr 14, 2014

I could understand void pointers I created the following program:

Code:
#include <stdio.h>
#include <string.h>
int main(void) {

char word[] = "Zero";
int number = 0;
void *ptr = NULL;

[Code] .....

The program works fine, however i really want to fully understand what is going on with the dereferencing of the void pointer, for example: With the following code:

Code:
ptr = &number;
*((int *)ptr) = 1;

Why can't you just do:

Code:
ptr = &number;
*(int *)ptr = 1;

And again with this code, (i'm guessing it's becuase its a pointer to a pointer?):

Code:
ptr = &word;
strcpy(ptr,"One");

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C :: Printing From Void Pointer

May 26, 2014

Code:
int main() {
List* newList= lst_new();
names* nama;
char* data;
int x=1;

[Code] ....

I cant seem to be able to print a string.. the functions lst_next() lst_first() return void*.

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C++ :: Void Pointer As A Parameter

Mar 14, 2013

I want to have a function that has a pointer to an int/double/string so I thought I'd use a void pointer like so:

int someFnc(int a, int b, const void *key){
// take care of converting key into appropriate type in here
}

And when I want to use this function I'd like to be able to do something like this:

main{
...
int myKey;
someFnc(1,2,myKey);
]

But I get a compiler error telling me:

invalid conversion from 'int' to 'const void' -[fpermissive]

Do I need to convert myKey into a void pointer before passing it as an argument?

Why does passing myKey like this work?

someFnc(1,2,&myKey);

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C/C++ :: How To Use Void Pointer Functions

Sep 27, 2014

int (*cInts)(void*,void*);
cInts= &compareInts;

int x=(cInts)(2,5); //This wont work. I tried a bunch of other things
printf(x);

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C++ :: Reference Pointer - Void Exchange

Mar 15, 2012

#include "vehicle.h"
...
void exchange(vehicle *&v1, vehicle *&v2) {
vehicle *tmp = v2;
v2=v1;
v1=tmp;
}

Is it right?

How about: void exchange(vehicle *v1, vehicle *v2){...}

What is the difference between *&v1 and *v1 ?

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C++ :: Error - Void Value Not Ignored As It Ought To Be

May 4, 2014

Using a template in the assignment, I don't know what I did wrong?

Code:
#include <iostream>
#include <string>
using namespace std;
template<class T>
void mpgcalc(T& Miles, T& Gallons)

[Code] .....

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C :: Sorted List - Why Value Of Void Pointer Change

Feb 16, 2014

I have a the following in a header file.

Code:

struct SortedList{
void * data;
struct SortedList * next;
struct SortedList * previous;
int (*compareFunc)(void *, void *);
void (*destructor)(void *);

[Code] ....

In a .c file, I implemented the SLCreate function.

Code:
SortedListPtr SLCreate(CompareFuncT cf, DestructFuncT df){
struct SortedList item;
item.data = NULL;
item.next = (struct SortedList *) malloc(sizeof(struct SortedList));

[Code] ....

In main.c, I try to do the following:

Code:
SortedListPtr list = SLCreate(&compareInts, &destroy);

A bunch other code that does not alter list or it's contents at all.

struct SortedList item = (*list);
void * data = item.data;
if (data != NULL) {
printf(Why did data become not null???
"); }

How come my variable data became not null anymore when I haven't altered it at all....

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C++ :: Multiple Of CSV File Used As Input / Extracting Data To A Output File - Getline Function

Jun 4, 2013

I have written a C++ program I have multiple of CSV file used as input, which I open one at a time and close it after extracting data to a output file which is the only file.

I run getline(inFile,line);
outFile << line << endl;

I run this code, and only part of it is goes to the output file I got, also have spacing randomly to specific file and inconsistent

But when I slower the code, like system("Pause") in the loop, I can get extract what I want perfectly....

Is my program running to fast, why getline would be skipping part of what things I want?

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