C++ :: How To Properly Use Pointer To A Particular Function
Apr 4, 2013#include <iostream>
using namespace std;
int function(int a,int b) {
return a + b;
} bool function2(int a,int b)
[Code] .....
#include <iostream>
using namespace std;
int function(int a,int b) {
return a + b;
} bool function2(int a,int b)
[Code] .....
This is my code for submitting students but when i use search function the course member is empty
Code: #include "windows.h"
#include "iostream"
#include <io.h>
#include <sstream>
#include <conio.h>
#include <stdlib.h>
#include <iostream>
#define SIZE 5
using std::cout;
using std::cin;
using namespace std;
int menu();
[code].....
i am facing some problem with qsort() function it work well if the last element of array is larger then the 2nd last element. But in case if last element of array is smaller then the 2nd last it will sort the whole array and remains the last as it is. For example
Code:
int group_id_local[max_j]={2,1,4,5};// it work fine, output should be {1,2,4,5} but if i have this one
int group_id_local[max_j]={2,1,4,3};
// output should be {1,2,4,3}
/* COMPARE FUNCTION FOR USING QSORT()*/
int cmpfunc (const void* a, const void* b)
{
if (*(int *)a < *(int *)b) return -1;
if (*(int *)a > *(int *)b) return 1;
return 0;
[Code]....
why it will not sort the last element?
I'm working with a cross-platform library which defines a function to obtain function addresses from a shared object (i.e. a DLL on Windows). Here's my modified version of the function which works (albeit only on Windows of course):-
Code:
typedef void (*SuilVoidFunc)(void);
/** dlsym wrapper to return a function pointer */
static inline SuilVoidFunc
suil_dlfunc(void* handle, const char* symbol) {
return (SuilVoidFunc)GetProcAddress((HMODULE)handle, symbol);
}
Now, here's the original (cross-platform) version which is giving me a run time error on Windows:-
Code:
typedef void (*SuilVoidFunc)(void);
#define dlsym GetProcAddress
/** dlsym wrapper to return a function pointer */
static inline SuilVoidFunc
suil_dlfunc(void* handle, const char* symbol) {
typedef SuilVoidFunc (*VoidFuncGetter)(void*, const char*);
VoidFuncGetter dlfunc = (VoidFuncGetter)dlsym;
return dlfunc(handle, symbol);
}
That original version fails at the final return line. The error message says "The value of ESP was not properly saved across a function call".
I'm assuming there's a problem with the declaration of VoidFuncGetter (i.e. it'll assume that the caling convention for GetProcAddress() is cdecl when in fact, it's stdcall). What's the most elegant way to fix this and still keep cross-platform compatibility?
Code:
struct lista* del(struct lista* p, char* path1) {
char model[MAX2];
int len;
char ch;
printf("Type model.
[Code] ..... t
This function should delete each element in the list which is the same as this one typed by user. There are no errors, but function doesn't work. It deletes something, but not this element which should.
I am unable to implement the insert function properly, every time i run the program i just get the first value and name, I am not getting other Id's and name.
"(Header File)"
#include <iostream>
#include <string>
using namespace std;
class node{
public:
int ID;
string name;
class node *left, *right, *parent;
[Code] .....
I'm working on a program which creates data and saves it into blocks (different files), then reloads and converts it all. the .ftl file saves properly, but for some unknown reason, it won't let me open it for input after.
Here's the significant code:
#include <iostream>
#include <fstream>
#include <string>
#include <sstream>
stringstream filename;
stringstream newfilename;
string Filename;
[Code] ....
setblock will typically = 3, but for testing purposes is set to 1. this really has me confused. the compiler i'm using is Dev-C++ 5.2.0.1 on xp. i have tried pausing the program after the output file is closed, confirming the file has been created in the proper directory before continuing but still fails the .is_open() check.
I tested my count funtion. So my count function is not working properly, it should return 5 because 5 words have prefix "tal," but it is giving me 10. It's counting blank nodes.
This is my main.cpp file
int main() {
string word;
cout<<"Enter a word"<<endl;
cin >> word;
string filename;
[Code] .....
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 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]....
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 ?
How this code work bcoz when pointer variable assigned in called function and how different values get as resultant output, ans 2 97 for below code. How the code wil execute so that i can validate ans
#include <stdio.h>
int main() {
int i = 97, *p = &i;
foo(&i);
printf("%d ", *p);
[Code] ....
I am trying to use "remove_if" with a predicate function inside a class. The code intends to remove the grid cells which an agent cannot move into (from among all possible cells).
Code:
void classname::function1()
{
vector<MoorePoint> neighbors;
....
[Code]....
That code would work if it was not in a class and the predicate was not a member function. However, now I receive long error messages which I guess refer to incompatibility of remove_if template with the predicate parameter (one error includes : error C2064: term does not evaluate to a function taking 1 arguments).
i need to pass myboard.board (board is in the class Cboard and it is an array of int) to a function in a class called piece however this is troubling . i need to pass it as pointer os that i could change its value here under is my code.
main.cpp Code: #include<iostream>
#include"board.h"
#include "pieces.h"
[Code].....
How to call a thread by a function pointer?
I get "error C2059: syntax error : '(' " on the indicated line.
Code:
#include <windows.h>#include <iostream>
using namespace std;
DWORD WINAPI Thread() {
cout << "ok" << endl;
return 0;
[Code] ....
I am trying to wright a program that takes student grade data from a command line file, calculates a final grade, and copies the final grades to an output file. So far I have two functions, one that creates a student structure by allocating memory for it and returning its address, and one that should take that address and fill it with data from a line from the input file. My ultimate goal is to use a linked list to connect all the structs, but for now I just want to get the functions working. When I run what I have so far, I get an error C2440 (using visual 2010) that says "cannot convert from 'cStudent *', to 'cStudent', and points to the line where I call my fill function. How should structure pointers be passed?
Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct student // Declaring student structure globally.
[Code] .....
Also, here is a sample of what a line from the input file would look like:
Bill Gates, 60, 54, 38, 62, 65, 60, 50
Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_CMD_LINE 500
void tokenize(char *cmd_ln, char *fun_tknzd[], int *argument_cnt);
[Code] ....
I am trying to pass the value of fun_tknzd to str_tknzd