We know that function pointer for virtual function are stored in a vtable.When we have multiple function pointer entry in vtable and we call one of the virtual function then how the corresponding or correct function pointer is retrived from Vtable? Who do this stuff? In assembly code i can not see any code or logic to detrmine the correct function pointer.
View 4 RepliesWhat would be the correct way to call a function within main that has file pointer parameters?
function prototype: Code: void CalculateBoth(int num1, int num2, int*sumPtr, int *diffPtr);
I want to implement some "debugger like" tool (very limited one, just identify at running time the current stack trace, and print messages from the user) on some code that the user wrote. what I get from the user is a function name (in the beginning of it's declaration), and when the user want to print some message he uses some print macro I should implement.
My target is printing the stack call, and all the messages that the user wrote, in the right place on the running place.
By what c++ feature can know on running time that a specific function code has ended??
Its easy to push a function to some vector when it called (since I get its name from the user), but when it ends and return to the function called it...
I'm not a programmer, at least, not a good one. I'm a researcher and I need to implement this function and test it and use it for my research. I tested some clustering methods in JAVA and Matlab and also I want to test it on C. I don't know too much about programming, especially about C, I know nothing. I tried to implement some basic methods but I failed.
It's all about K-Means Algorithm. I'm working on a disease and I'm trying to find ways to early diagnosis. Anyway, these are details. The thing is, I found a 'free to use' function but I don't know how can I use it. I tried to learn something from Net, I downloaded a compiler, I paste the code and I get many errors... And I heard that I have to do some "calling function" stuff but I don't know how to..
The code is in the link below: URL....It's not imperative that using this function, it can be another one but it had to written in C.
I'm trying to call a function via a function pointer, and this function pointer is inside a structure. The structure is being referenced via a structure pointer.
Code:
position = hash->(*funcHash)(idNmbr);
The function will return an int, which is what position is a type of. When I compile this code,
I get the error: error: expected identifier before ( token.
Is my syntax wrong? I'm not sure what would be throwing this error.
I have been trying to make a function that compares all the values of the array and if they are all equal will return a value to print true. The problem I am having is that regardless of what values I enter the function is always returning true. Any way to tell the program o check all the values in one command instead I put them each,
Code:
#include<stdio.h>
#include<stdlib.h>
int compare(int arrayA[], int arrayB[]);
[Code]....
Ok, so the assignment is to use a recursive function to display a request for a certain position in the Fibonacci Sequence (0, 1, 1, 2, 3, 5, 8, 13...)
The program I have written works, but it displays the wrong number in sequence. The book says that when you enter "8" you should receive "13", which is correct in the order of the sequence, though my program is producing "21" which is the next number in the sequence.
I tested it with a few more numbers and when I enter "7" it produces "13" and when I enter "6" it produces "8" and so on.
Code:
//Cameron Taylor
#include <stdio.h>
int main(){
[Code].....
For whatever reason, I get an error meassage about lines 53-57 saying there is no matching function to call to. Yet the header and the prototype are correct (I think anyways).
#include <iostream>
#include <string>
#include <fstream>
#define N 10
using namespace std;
class cust{
[Code] ....
I have to write a code which would determine either a URL address is correct or not.
Now, a valid address should look like: "www.something.something.uk".
It has to have 3 dots, 3 w-s in the beginning, and it must end with "uk".
E.g.
Valid addresses:
1. www.jce.ac.uk
2. www.tr2213.oi34.uk
Invalid addresses:
1. www2.jce.ac.uk
2. òæøéàìé - îëììä à÷ãîéú ìäðãñä éøåùìéí - ìéîåãé äðãñä ìúåàø øàùåï
3. www.something.uk
Just to be clear, this criteria mentioned above is not real, just homework
Code:
#include <iostream>
#include <string.h>
using namespace std;
int isValid (char s[])
{
int dots=0;
[Code] ......
It tells me both strings are incorrect but the first 1 is.
I have this homework where i am implementing a code which does error checking
so basically i have 3 variables and i assigned them as integer. so my error check is asking that if i type a value for instance 1.2 it should output "X"...
#include<stdio.h>
#define TRUE 1
int formOddInt(int n);
[Code]....
I wanna write a class for polynomials, but there are some bugs in my code. I want to identify a polynomial with two arrays of the same length, one that contains the exponents of the nonzero monomials, and the other that contains the coefficients itself.
for example: (shematically)
3x^2 +5x^100 shoud be identified by array1=(2,100) and array2=(3,5)
the size of that polynomial should be Dim=2.
it should be possible to change the size dynamically.
Code:
#ifndef poly
#define poly
#include<cassert>
class poly {
[Code] ....
PROBLEM1 the destructor isnt working:
virtual ~poly() {delete [] start;delete [] koef;} //destruktor
Error: This declaration has no Storage class or typ specifier.
Error: Expected an identifier.
PROBLEM2 the constructor isnt working:
poly::poly(int x=0)
Error: Expected an identifier
Error: Expected a )
Error: Expected a ;.
I dont know what the computer want to tell me??
I am attempting to implement function pointers and I am having a bit of a problem.
See the code example below; what I want to be able to do is call a function pointer from another pointer.
I'll admit that I may not be explaining this 100% correct but I am trying to implement the code inside the main function below.
class MainObject;
class SecondaryObject;
class SecondaryObject {
public:
[Code]....
I have a dialog app with two separate static controls. Both controls have been subclassed from CStatic derived class to implement drag and drop and double clicking. The class works just fine, but I cannot figure out which of the controls is being double clicked or dragged and dropped onto because I only have the code below operating. I need some method in the derived class to determine which control is being manipulated.
Code:
// header file
#pragma once
#ifndef __AFXWIN_H__
[Code]....
Identify the invalid C expression or choose "all are valid". Assume all variables are integer and non-zero.
7.
a) a+b-0 b) c+-a%4 c) xm6-24 d) xf3r6+2
e) all are valid
8.
a) xx+yy%zz b) z%(z%z%z)) c) ha+ha+ha d) x23-20.4
e) all are valid
[Code] ......
I am supposed to make a histogram. I succeeded in generating the integers for the histogram. But what I want to do is instead of displaying numbers in the console, I want something like "*" displayed for every integer there is in an array. It should look something like this.
*
****
*****
********
**********
******
****
***
*
As far as I understand, in some way I need to identify the integer in the array and for every single one of them I need to insert the symbol. I don't know how to identify it.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication1{
class Program {
static void Main(string[] args) {
diceHistogram();
[Code] .....
int example (int [], int, *int,*int,*int,*int);
int main () {
My code will be here
example (int array[], int size, &a,&b,&c,&d); // Like this??? I try it didnt work
[Code] ....
I tried to use pointer with a function but I guess I am missing out on something
Code:
#include<stdio.h>
int add(int *a,int *b){
int *c,*d;
*c = *c+1;
*d = *d-1;
[Code] ....
And this one too
Code:
#include<stdio.h>
void add(int *a){
int *c;
c = c+1;
[Code] ....
I was wondering what magic does a * pointer before function actually do? Today our programming teacher asked us to look into it and explain it in the next class!
#include<iostream>
using namespace std;
int *binary(int []);
[Code].....
How can we assign a pointer to a function? const char* function_name(), here what exactly does the pointer point to?
View 4 Replies View RelatedCode:
void dereference(int* a, int* b)
{
a=b;
}
int main(int argc, char **argv)
[Code] ....
Why isn't f and d the same after calling "dereference(f,d);"
As the title says, i'm using a function which returns a pointer to a struct:
the struct is the following:
Code:
typedef struct POINT
{
uint16_t x;
uint16_t y;
}
Coordinate; the function i'm using:
Code:
Coordinate * Read_XTP2046(void)
{static Coordinate screen;
//calculations to determine the coordinates
screen.x=(temp[1]+temp[2])/2;
screen.y=(temp[0]+temp[2])/2;
// and so on...
return &screen;}
The question is: how do i catch this pointer and make it into a Coordinate struct in which i can read the x and y.
In my main program i would do the following:
Code:
Coordinate cor;
cor = Read_XTP2046();
This does not work, as the function returns a pointer, but how to transform this pointer into a Coordinate struct.
I would like to initialize an arry containing function pointers with adresses of functions that have a variable number of arguments.
Below the code that works in principle. I would however get rid of the warning message during compilation pointing to the initialzation of the funtion pointers in the array. How do I need to cast the pointers to the functions ?
Code:
gcc func_ptr_init.c
func_ptr_init.c:28: warning: initialization from incompatible pointer type
func_ptr_init.c:32: warning: initialization from incompatible pointer type
Code:
#include<stdio.h>
unsigned char func1_ptr(unsigned int* if_desc, int* result_code) {
*if_desc = 1;
*result_code = 1;
return(0);
[Code] ....
I am trying to return a pointer from a method. Below is a sample of my code.
CSubnode * CTest::GetSubNode() {
return m_psubnode;//this is declared in CTest as CSunbnode * m_psubnode
}
//in another class
m_subnode = m_ptest->GetSubNode(); //m_subnode is declared as a pointer
Is this the correct why to return a pointer?
I declared a pointer in main with value 0, so I want to change its value so that it points to other variable from a function, I guess the function creates a copy of my pointer that's why whatever I do within function doesn't change the real direction of the pointer in main. I've been trying something like this:
#include <stdio.h>
void redirectionate(char *str, char *ptrCopy);
int main()
{
[Code]....
two things I did'nt get till now
Q->1 what is the actual use of function pointer ?
Q->2 what is use of passing function as an argument to another function ?