C :: How To Use Pointer To Struct
Mar 6, 2015how can I call and print the Pointer:
ptr->address
Code: #include<stdio.h>
struct account {
int address;
int value;
[code]....
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C++ :: Accessing Inside Structure Via Struct Pointer To Struct Pointer
Jun 5, 2012"
#include <stdio.h>
struct datastructure {
char character;
};
void function(struct datastructure** ptr);
[Code] ....
These codes give these errors:
error: request for member 'character' in '* ptr', which is of non-class type 'datastructure*'
error: request for member 'character' in '* ptr', which is of non-class type 'datastructure*'
These errors are related to
"
*ptr->character='a';
printf("Ptr: %c",*ptr->character);
"
I want to access "character" data inside the structure "trial" by a pointer to pointer "ptr" inside function "function",but I couldn't find a way to do this.
C/C++ :: Source Code Containing Struct Pointer
Mar 9, 2015#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main() {
struct stock{
char symbol[5];
int quantity;
float price;
[Code] ....
- In the final output
Value
%.2f
- How is the final pointer reference at line33 leading to the output %.2f ? (i do understand that the %% is used to display a %] ....
C/C++ :: Printf Several Values Of Struct Pointer?
Jan 14, 2015I am currently trying to printf several values of a struct pointer but with little success.
#include"Header.h"
/*
In header:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <conio.h>
struct FileStruct {
char FileQuestion[64];
[Code] ....
As you can see I am trying to re-crate the output from the first loop in my second loop, however it is with little success. The second loop's first run re-crates the last output of the first loop and if I use FileStructPointer++ or -- the output goes broke.
See attached for how it looks in the console window.
Attached image(s)
C :: Function Pointer Inside A Typedef Struct
Aug 25, 2014I want to have a function pointer inside a typedef struct but I get a segmentation fault when I run my code. Here's my code:
#include <stdio.h>
typedef struct Foo {
void (*bar)(int);
} Foo;
void func(int x) {
printf("display: %d
[Code] ....
C++ :: How To READ Pointer Of A Struct Type In File
Nov 23, 2013This is a c++ Code. I want to read a address to a pointer. When I try to do so it generates an error. I did is >> obj1[0].contentAdress; in main.
struct node3{
node3(){
nextContent = NULL;
for (int i = 0; i<1020; i++)
content[i] = '';
[code]...
no operator found which takes a right-hand operand of type 'node3 *' (or there is no acceptable conversion)
C++ :: Initialize Char Pointer Array In Struct
Nov 28, 2014I am trying to store data in a struct to be able to read it latter . have problems initializing this.
struct FoodAndDrink {
struct Food {
char* CannedGoods[2] = {
"Canned Spaghetti",
"Canned Tuna",
[code] .....
C++ :: Return Struct Pointer From A Void Function And Print
Mar 17, 2013i 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...
C/C++ :: Sizeof (struct) Returns 6 More Bytes Than Actual Struct Size?
Sep 14, 2014#include <stdio.h>
#define MAX_USERS 20
struct {
char ID[10];
char Name[40];
int Pos;
[Code] .....
I was attempting something weired with address to move data around when I discovered that the size of the array is not what I expected. I am passing this structure as &Users to a function that declares it as a void *, then I can deal with chunks of data (memmove) and not have to worry about index or things like that. However...sizeof is returning something I do not understand.
C++ :: Creating A Struct Within Struct Node?
Feb 28, 2015Im having trouble creating a struct within a struct node. the program suppose to hold students firstname, lastname, and gpa in a node therefore creating my linked list. Line 26 keeps saying that cannot convert parameter 2 from 'studentType to std::string
#include <iostream>
#include <string>
using namespace std;
struct studentType{
string firstname;
string lastname;
double gpa;
[code].....
C++ :: Struct Inheriting From A Class Or A Class Inherit From A Struct?
Mar 9, 2012I just read and have known for a while that classes are private (members and inheritance) by default and structs are public. But my question then comes what if.. a struct inheriting from a class or a class inheriting from a struct?
View 3 Replies View RelatedC++ :: Linked List Node Passed As Parameter / Argument Pointer To Pointer Notation
Jan 17, 2014I was having problems changing the value of my head node I passed it as an argument as head which would be the address. The parameter was defined as struct node *head. like this
bool deleteNode(struct node *head, struct node *delptr)
I tried manipultaing pointer values to change head node value but it did not work. I saw some code online which used pointer to pointers(in code below) to change head node value it worked I dont fully understand why. Would like better understanding of why.
Would also like to know why the argument call needed &head instead of just head.
remove = deleteNode(&head,found); opposed to remove = deleteNode(head,found);
#include "stdafx.h"
#include<iostream>
struct node{
[Code].....
C++ :: Calling Defined Function Pointer From Another Pointer To Class Object?
Aug 19, 2014I 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]....
C :: Print Pascal Triangle And Stores It In A Pointer To A Pointer
Nov 27, 2013I have to write a program to print pascals triangle and stores it in a pointer to a pointer , which I am not entirely sure how to do. I also have to write the file and read it, then create a binary file. Assignment is attached. I am not the best with programming and especially with pointers. I will post my code below.
Code:
#include <stdio.h>
#include <stdlib.h>
void writePascalTriangle(char *fileName, int heightOfTriangle, int **triangle) {
FILE *fp;
fp=fopen("writePascalTriangle.txt", "w");
[Code] ....
C++ :: Get Pointer That Iterator Points To And Store In Pointer Variable?
Apr 19, 2014I'm making a system like twitter for class called ShoutOut.com I want to be able to get the PublicShoutOut pointer pointed to by the start iterator and assign it to firstShoutOutToDisplay and secondShoutOutToDisplay because I need that in order to pass the pointers to one of my functions. When I step through the debugger the values in start are all default values like "" and so are the values in this->firstShoutOutToDisplay but the message that start points to is being output just fine.
EDIT: got rid of irrelevant code. Am I using the correct syntax to do this?
if (start != finish) {
//getting these because a shoutout needs to be passed to the function that displays
//options for a shoutout
this->firstShoutoutToDisplay = (*start);
[Code] ....
C++ :: How To Convert Void Pointer To Int / Double / String Pointer
Mar 7, 2013I 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?
C :: Access Element Of Array Through A Pointer To A Pointer
Dec 25, 2013i have been fiddling with pointers but I don't understand how the proper syntax is written when I want to acces an element of an array through a pointer to a pointer...The code is all mostly just random bs for learning purposes. I marked the problem "// THIS LINE"
Code:
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#define MAX_DATA 100
int find_average(char *iden, ...) {
[Code]...
C :: How To Declare Two Dimensional Array Using A Pointer To A Pointer
Jul 16, 2013This is a sample program that declares a Matrix as a structure with an array as a pointer to a pointer. The following program is supposed to store a matrix in the structure "_Matrix" and later print the matrix just entered but it fails giving me a "segmentation fault". The sample code is given below
Code:
#include <stdio.h>
#include <stdlib.h>
struct _Matrix {
int row_size;
int col_size;
int **mat;
[Code] ......
C++ :: Pass Matrix By Reference Using Pointer Of Pointer
Jun 20, 2014i really don't know why has a error in my code, that pass a pointer of pointer (name of a matrix with 2 dimensions). Here is the source code of a simple example where appears segmentation fault when execute (but compiles normal):
#include <stdio.h>
#define LINHAS 3
#define COLUNAS 5
float a[LINHAS][COLUNAS];
void zeros(float **p,float m, float n){
int i,j;
for(i=0;i<m;i++)
[Code]...
C/C++ :: Copying A String From A Pointer To New Pointer
Mar 4, 2015I need to make a copy of a string that is defined by char *full and copy it into a different pointer defined by char *duplicate. I have written code to do this however it will not work and i cannot figure it out my code is as follows:
char *duplicate = (char *)malloc(strlen(full) + 1);
strcpy(duplicate, full); /*Make second version of full*/
char *Ptr = strtok(duplicate, " "); /*Split duplicate up*/
I have a full program written but i know this is where the problem is because i have used printf statements to see where the program fails. I get no errors and it compiles successfully but it hits this point of the program and it just stops and windows automatically shuts down the program.
char *full is pointing to:
"To be, or not to be? That is the question:
Whether 'tis nobler in the mind to suffer
The slings and arrows of outrageous fortune,
Or to take arms against a sea of troubles,"
I need to duplicate the string because i need to use strtok but i will need the original string later on so i need an unaltered version.
C++ :: Looping Through 2D Array Using Pointer To Pointer
Jan 3, 2013I have the following code :
Code:
#ifndef TDYNAMICARRAY_H
#define TDYNAMICARRAY_H
namespace Massive {
template<class T>
T **AllocateDynamic2DArray(int nRows,int nCols)
[Code] .....
I wish to know how to traverse or loop through a dynamic 2D array using pointer to pointer as returned by the code above. Like I would in a static T[20][20] 2D array.
C :: Calling Function Via Function Pointer Inside Structure Pointer
Mar 14, 2013I'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.
C++ :: Cast Base Class Pointer To Derived Class Pointer
Feb 6, 2015I create an instance of a base class (not derived class) and assign it to base class pointer. Then, I convert it to a pointer to a derived class and call methods on it.
why does it work, if there is a virtual table?
when will it fail?
// TestCastWin.cpp : Defines the entry point for the console application.//
#include "stdafx.h"
#include <iostream>
class B
{
public:
B(double x, double y) : x_(x), y_(y) {}
double x() const { return x_; }
[Code] ....
C++ :: Pointer Point To Pointer?
Jan 30, 2014Is this the correct format to point a pointer (pointer1) to another pointer (pointer2)?
&pointer1 = &pointer2
I am kinda rusty when it comes to pointers ...
C++ :: Getting Segfault With Pointer To Pointer?
May 19, 2013I'm trying to store an array of vectors using a double pointer as a 2D array, but after the first "vector" (column) has been filled, I get a segfault. I correctly included all the libraries needed, and declared all the variables; I am using this function to allocate the space for the array:
double **vec_array(int rows,int clms)
/*allocates a double matrix with -rows- rows and -clms- columns */
{
int i;
double **m;
[Code].....
I get no error while compiling, but when I run the program I get a segfault right after having read the first vector: switching on the check I get in my output just the components of the first vector and then the segfault:
Terminal:
$ ./myprog input_data.dat
0.000000 0.512468 -0.152468
Segmentation fault (core dumped)
C++ :: Having Struct As A Key For A Map
Oct 24, 2014So why does this not work? As an example:
struct example {
int x; int y;
};
int main() {
example variable;
variable.x = 1;
variable.y = 2;
map<example, int> something;
something[variable] = 3;
return 0;
}
And I get a very long error message from the compiler. I tried using an enum as the key as well and that worked just fine, but I guess that's just the same as having an integer as the key. But anyway, what's the problem with this? Is there any way to make it work?