C++ :: Initializing Double Pointer Array?
Aug 1, 2013How to initialize double pointer array..?
int (**aLines)[2];
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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++ :: Initializing A Class To A Pointer?
Feb 4, 2014I came across a piece of c++ code that seems to be initializing a class object like this:
ImapMailbox *mailbox;
Now the class looks like this:
class ImapMailbox {
public:
ImapMailbox();
ImapMailbox (const QString& mailbox);
~ImapMailbox();
// Methods
void addMessage (ImapMessage *message);
[Code]...
And the constructor looks like this:
ImapMailbox::ImapMailbox()
: d(new ImapMailboxPrivate)
{
d->unseen = d->exists = d->recent = 0;
d->readWrite = false;
d->flags = 0;
}
But this does not seem to be an array like object. So what exactly could this be pointing to?
C/C++ :: Initializing Pointer To NULL?
May 17, 2014So I'm writing a small program for class, and for some reason I keep getting an error when trying to initialize head to NULL. Even threw in the namespace just to see, nothin'.
#ifndef NUMBERLIST_H
#define NUMBERLIST_H
using namespace std;
[Code].....
There's my header file. Not sure what I'm doing wrong with the constructor.
EDIT: Got it to work with nullptr, but still curious why that isn't working
C++ :: Double Pointer - Dynamic Allocation
Oct 24, 2013I'm writing a program involving a theoretical hotel. Most of the code is already written, but the part I'm having trouble with involves the very beginning of the code.
The program is designed to read in from an input file the hotel's ID number, the types of rooms it has, the Room Numbers of each room, the base rate for each room, and the rate of additional charge per person.
The code demonstrates inheritance for my Object-Oriented Programming class, as each type of room will inherit from generic class Room, but I can't seem to figure out how to make the double-pointer for dynamic allocation work.
The code is below.
Hotel.h
Code:
class Hotel{
int hotelID;
static const int MAX_SIZE = 101;
Room **rPoint;
[Code] ....
C :: Assign Strings To Double Pointer
May 2, 2013When I try to assign strings to a double pointer, it only prints out the last string when I try to print everything out, and then it segfaults.
Code:
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
main(){
char **test = calloc(3,sizeof(char));
[Code] .....
Am I assigning something the wrong way? Also, I am trying to avoid using array notation in order to practice, at least for the assigning of the strings.
C :: Reading Words Into Double Pointer?
Apr 22, 2013I have a double pointer, and I need to read words into it. Here's what I have so far:
Code:
while(fscanf(keywordFile,"%s",keyinputter)==1){
keys_cnt++;
}
keywords = (char**)calloc(keys_cnt,sizeof(char));
[Code]....
keyinputter is an array of size 30. The first while loop finds the number of words in a file so that I can calloc the correct amount of space for the double pointer, keywords. The second while loop is supposed to read the words into the double pointer, but when I run a print statement to print the string at keywords[0], it only prints null and not the word. Am I assigning the strings to the double pointer in the wrong way?
C :: Double Use Of Arrow Operator With Pointer / Function
Feb 24, 2015I have recently come across a function call that I do not understand. It uses the arrow operator for a function call, twice, and I don't understand.
Code:
static inline void b43_write32(struct b43_wldev *dev, u16 offset, u32 value)
{
dev->dev->write32(dev->dev, offset, value);
}
I see that the function itself does not return anything but calls another function. The main difficulty I have is with the "dev->dev->" operator, where dev, I expect is a pointer to a structure.
C/C++ :: Converting Int To Double Pointer Outside Main Function
Dec 22, 2014I have int pointer called p and i want to calculate average.Since average involves using double or float so i am trying to convert this in the function averagetemp. It still gives me an error saying "cannot be converted"...
#include <iostream>
using namespace std;
int* createArray(int n);
int lowesttemp(int *p,int f);
int highesttemp(int *p,int f);
double averagetemp(int *k,double f);
void print(int *p,int lowest_temp,int highesttemp,int average_temp);
[Code] ....
C :: Why Most Examples Pass Double Pointer When Manipulating Linked Lists
Mar 1, 2014Why do most C examples pass a double pointer when manipulating linkedlists? Why can not we just pass a single pointer to the struct?I think using an external reference accessor for a linked list would be a more appropriate solution, yes or no?
View 1 Replies View RelatedC++ :: Pass Double Pointer Of Object Into A Node Of Self Similar Type?
Nov 30, 2014The following code compiles and runs fine till it reaches line 16 and gets a sigsev violation which I'm not sure about as to why. I have no problem passing the object of type node** into the constructor of base and storing it into the double pointer node** copy;; but when I call the function void pass(node** temp) it crashes.
#include <iostream>
class base;
class node {
private:
node** data;
public:
[Code] .....
C++ :: Constructor Not Initializing Array?
Mar 6, 2015I am making a tictactoe program that requires me to have a 3 by 3 two dimensional array of integers, in which the constructor should initialize the empty board to all zeroes. The program complies, but it keeps outputting garbage values and i'm not entirely sure why, My print function isn't complete yet, since I want to print out the array in a tic tac toe format, but i'm more concerned with why it's printing garbage values, here is my code:
Code:
// header file
#include <iostream>
#include <array>
[Code] ....
C/C++ :: Initializing Array Of Structures
Feb 25, 2014How to initialize this array of structures in my code
struct CustomerAddress; {
string street;
string city;
string state;
int zip;
[Code] ....
I am going to be using a boolean variable to mark whether or not a specific field has had data entered into it. I figure the best way to do that is to initialize all the elements of the structures to 0. However, with strings and with the nested structure, I'm not sure how to do this.
C++ :: Initializing 2D Dynamic Array With All Entries 0?
Dec 29, 2013is it possible to create a dynamic array with all entries in it equal to 0?
int** adjMatrix;
adjMatrix= new int*[numOfVertices];
for(int i=0; i<numOfVertices; i++){
adjMatrix[i]=new int[numOfVertices];
}
C++ :: Initializing Local One Dimension Array?
Jul 31, 2013Want to initialize a local one dimensional array. How can I do the same without a loop?
Found from some links that
int iArrayValue[25]={0};
will initialize all the elements to ZERO. Is it?
If yes then can we write below code to initialize the elements to a non-ZERO value?
int iArrayValue[25]={4};
Do we have some other way to initialize an array to a non-ZERO value? Memset can initialize the element to ZERO.
C++ :: Initializing Multidimensional String Array?
Nov 15, 2014In one of my programs I have a 3x3 array of string that I use to display the outcome to rock, paper, scissors, and another 1x3 used for a number guessing game. I have the arrays declared in the header file as follows:
//Games.h
std::string rpsOutcome[3][3];
std::string hiLoOutcome[3];
and then initialized them in the cpp file:
//Games.cpp
string rpsOutcome[3][3] {
//row 1
{ "Both of you picked rock, you tied. Try again",
"You picked rock, the computer picked paper, you lose",
[code]....
From what I've read, Im pretty sure thats how your supposed to initialize multidimensional arrays (using the nested braces), but when I build the project, I get the following error:
123456789101112
1
1> RockPaperScissors.cpp
1> Games.cpp
1>c:userswuubbgoogle drivevisual studio projectsgamesgamesgames.cpp(75): error C2374: 'games::rpsOutcome' : redefinition; multiple initialization
[Code] .....
C++ :: Crash When Initializing Indices Array
Nov 26, 2012Why I get a crash when initializing the indices array below (bottom)-
Code:
struct TerrainGroupData {
TerrainGroupData(){};
TerrainGroupData(Ogre::Vector3 ** iVertices, unsigned long ** iIndices, size_t* iFaceNum, size_t* iVertNum) {
vertices = iVertices;
indices = iIndices;
[Code] ...
Visual C++ :: Initializing Array In Constructor?
Mar 8, 2015I am making a tic tac toe program in which they are asking me to have a 3x3 2 dimensional array of integers and have the constructor initialize the empty board to all zeros. They also want me to place a 1 or 2 in each empty board space denoting the place where player 1 or player 2 would move The problem I'm having is, my code initializes the board to all zeros for each element of the array, and prints it out just fine, but I can't figure out how to re-initialize the values in the array to show where each player moves on the board... I was thinking about having a default constructor that has each value set to zero, and then use a setGame function that can change the values on the board to one or two depending on where the player moves....but I don't know if that's possible.....
here is my code
Code:
// header file
#include <iostream>
#include <array>
class tictac {
public:
tictac(int);
[code]....
C++ :: Initializing Array Of Char Pointers Directly
Nov 24, 2014I'm learning OpenGL using the C API and some of the functions' argument types have proven a bit challenging to me.
One example is the function Code: glShaderSource(GLuint shader, GLsizei count, GLchar const** string, GLint const* length); It resides in foo() which receives a vector "data" from elsewhere Code: void foo(std::vector<std::pair<GLenum, GLchar const*>> const& data); To pass the pair's second element to glShaderSource's third argument, I do the following:
Code:
GLchar const* const source[] = {data[0].second};
glShaderSource(..., ..., source, ...);
Now I have two questions regarding this:
1. Can I initialize a char const** via initialization list, the way I do a char const*?
Code:
// this works
std::vector<std::pair<GLenum, GLchar const*>> const shader_sources = {
{GL_VERTEX_SHADER, "sourcecode"},
{GL_FRAGMENT_SHADER, "sourcecode"}
};
// but is this possible?
std::vector<std::pair<GLenum, GLchar const**>> = { ??? };
2. Is there an alternative to creating a temporary GLchar**, even though that's specifically what the function wants?
C :: Declaring And Initializing 3000 Number Array?
Oct 23, 2013Here are the steps to this program:
1. Declare an array that will hold 3000 numbers
2. Initialize this array by assigning a random number to each element in the array
3. Traverse the array, modifying the current contents of each element in the array so that each value now lies between -3000 and 3000 inclusive
4. Traverse the array to compute the average value of all elements
I have never worked with arrays before and am lost!
C++ :: Initializing N-dimensional Array With A List Of Components
Nov 7, 2014InitializeNArray<4, bool, NARRAY>()(narray, {1,2,3,2}, true);
is supposed to initialize a 4-dimensional std::array a with a[1][2][3][2] = true.
The commented-out line, which is the desired recursion, does not compile for some reason, and the problem third parameter cannot be deduced. So I placed some temporary lines to work in the special case only. Howw to make that recursion work?
#include <iostream>
#include <array>
#include <vector>
#include <memory>
template <typename, int...> struct NArray;
[Code] ....
Incidentally, this is a sub-problem within the task of initializing more generally with
template <typename T, int... N, typename... ARGS>
typename NArray<T, N...>::type NDimensionalArray (const T& value, ARGS&&... args)
Once this subproblem is fixed, then the bigger task is fixed too.
C++ :: Initializing Array Of String Type In A Class
Apr 28, 2013I want to use this array as part of my class. I have tried several different angles trying to get it to work but with out success. I have been checking to see if it works by simply using "cout << dayName[3];" It is printing nothing at all. What is the proper way to initialize this array of strings?
First I tried this:
const string dayName[] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};
then I tried this:
const string dayName[7];
dayName[0] = "Sunday";
dayName[1] = "Monday";
dayName[2] ="Tuesday";
dayName[3] ="Wednesday";
dayName[4] ="Thursday";
dayName[5] ="Friday";
dayName[6] ="Saturday";
My implemetation file code and my header file code is here (header first):
//dayType.h, the specification file for the class dayType
#include <iostream>
#include <string>
using namespace std;
class dayType{
[Code] .....
C++ :: Global Char Type Array Initializing
Mar 20, 2015I am not getting any error below
--------
#include <iostream>
using namespace std;
void main()
{
char sqr[3];
sqr[0] = '1';
sqr[1] = '1';
cout << sqr[0] << sqr[1];
while (1);
}------------
but if I move my char type array before main , I get error l
----------------------------
#include <iostream>
using namespace std;
char sqr[3];
sqr[0] = '1';
sqr[1] = '1';
void main()
{
cout << sqr[0] << sqr[1];
while (1);
}
-------------------
C/C++ :: Accommodate Double-size 8 Bytes In 4 Bytes Pointer In 32bit System?
Mar 15, 2015how to accommodate double-size:8 bytes in 4 bytes pointer in 32bit system.
View 1 Replies View RelatedC++ :: Should Use Vector Or Just Double Array
Dec 15, 2014I am programming about some numerical problems. I know that vector supplies vector operations. But vector always allocate more memory (used when the size changes). My matrix or array never change size, and the vector operation is just +,-,dot,cross,distance
My question is that should I use vector, or simple double array with new & delete is enough for me?
C++ :: Getting A File Into A Double Array?
Dec 20, 2014The assignment is to create a program that lets users reserve a spot on a plane either in coach or first class. I'm supposed to create a .txt file to use as the prices for different seats and while I have done that, I'm having trouble getting the file into a double array.
This is what I have so far.
//This program lets the user reserve airline tickets on a plane
#include <iostream>
#include <cstring>
#include <fstream>
using namespace std;
[Code]....
Once I have the file into a double array, I have to use that array to implement it into the seat prices. Such as if user chooses to sit in row 1 seat 1 it would be that price. Also the '#' means open seat and '*' means seat taken. O yea, under the "//Populating the double array" is me trying to see if a for statement or a nested for statement would work.