I have a class called Book and I am trying to create a dynamic pointer based array of the class. When I try to run the program I keep getting the error: pointer being freed was not allocated at the line of code that says "delete [] A;". I am using Xcode to run the program.
Book *changeArraySize(Book *A, int &size, double factor) {
int i;
int newsize = size*factor;
Book *A2 = new Book[newsize];
[Code] ....
I'm completely new to pointers and have a homework assignment due where I'm supposed to create a user defined dynamic array for player scores. The only errors I'm experiencing is a C2109: subscript requires pointer type and only on the lines that use the int *score; variable (57, 62, 64, 69, 71, and 82). I've already tried adding = nullptr to the variable and that didn't work.
#include<iostream>
#include<string>
#include<iomanip>
using namespace std;
void players(string[], int[], int);
void average(int[], int);
[Code] ....
I have a struct called Array and I'm to create a function to create a dynamic array that's fill with randomly generated integers from 0 to 50 (inclusive) and a function to destroy the array for freeing its memory. Below the code that I have written so far.
Code:
* Struct */
typedef struct {int *pArray; //the dynamic array
int length; //the size of the dynamic array}Array;
/* Function to create a dynamic array */
Array *initializeArray (int length) {int i;
}
[code]....
What is wrong with my function why does it spit out huge numbers? And how do i use malloc or calloc to create an array in dynamic memory, and return a pointer to this array
Code:
#include <stdio.h>#include <stdlib.h>
int fibonacci(int n)
{
int i;
long int fib[40];
fib[0]=0;
fib[1]=1;
for(i=2;i<n;i++){
fib[i] = fib[i-1] + fib[i-2];
[Code]....
Create in the private section of the ServerGroup class a pointer to a dynamic integer array called servers.
#ifndef ServerGroup_h
#define ServerGroup_h
class ServerGroup {
public:
private:
int *ptr = new int; // needs pointer to a dynamic integer array called servers
};
#endif
In case the question was not very clear. Say I have the following code:
int sum(int * x, size_t N){
int sx;
/* returns sum of elements in x */
return sx;
[Code] ....
I'm curious to know whether there is a way that ensures a function does not modify the memory pointed to by a pointer.
i am trying to create the assignment operator for a class that uses a pointer for it's private variable. The error is saying expected constructor, deconstructor, or type conversion before "operator. (which is the assignment operator. I have tried everything i could think of or find online and nothing has worked. below is the code for the assignment operator in the .h file and the .cpp file.
//Assignment constructor
indexList &operator=(const indexList <T> &rhs);
template <class T>
indexList<T>::indexList operator=(const indexList <T> &rhs) {
if(this != &rhs) {
numberOfElements = rhs.numberOfElements;
[Code]...
I need to create a main function with a one dimension dynamic array with float data type. The total number of array elements must be controlled by a user input from the keyboard. Test data is three different lengths 3,6,9 of the array. The lengths have to be set up at run time from users input. I understand how to create dynamic array but not where the user inputs the length of the array. How would I implement this?
View 6 Replies View RelatedI was writing generic class Array (based on counting access to elements)and i got compiling error I cannot even understand (in vs2012).
Code: [URL] ....
Error: [URL] ....
How do I copy from a dynamic array initialized in a class but with a different memory address. For example if my array is a dynamic array initialized in a class...
Code:
const int CAPACITY=5;
class Array{
public:
Array();//constructor
[Code] .....
How would i copy this array to a another array but have a different memory address so when i deallocate array a my copy array also isn't deallocated.
// dynamic memory for 2D char array
char **board = (char**) calloc(column, sizeof(char*));
for(int i=0; i<column; i++)
board[i] = (char*) calloc(row, sizeof(char));
//for char 255 row and colum
char temp[255];
inputFile.getline(temp,255);
[Code]...
so i want to change into vector class like Vector<board>row;
I'm writing a class that has two constructors. However, I can't get them to work quite right. One constructor has a parameter of an int (with a default value of 0) and the other has a parameter of a C-style string.
First of all, are these function prototypes correct for the constructors?
MyInt(int n = 0);// first constructor, int param, default value 0
MyInt(const char * c);// second constructor, c-style string param
Both constructors work fine in some cases but don't work in all cases. Here are some potential calls to these functions that are supposed to work:
// These two work fine
MyInt x(12345),
y("9876543210123456789"),
// The array assignment doesn't work when the value is negative
// I'm not allowing negative numbers, but I want to create the object and assign the array to 0
r1(-1000),
[Code] .....
Here's the private data from the class (from the header file):
private:
int currentSize,
maxSize;
char* digits;// Pointer to an array of digits
// Increase the size of digits array by 5
void Grow ();
I attempted to create a dynamic array class for use in my engine (due to problems regarding a dll-interface with the standard library), so I tried at making a standard-compatible allocator template class first. After I "finished" that, I went on to work on the dynamic array class itself.So I finish the dynamic array class, and test it with the standard allocator. It works perfectly, but when I test it with my custom allocator class, it fails terribly.
To make sure it wasn't my DynamicArray class that was causing issues, I tried using the custom allocator on the std::vector class template, and it didn't work either. IMy DynamicArray class code:
// Represents a dynamic array, similar to the standard library's "vector" class.
template<typename T, typename A>
class DynamicArray
{
public:
DynamicArray() :
data(nullptr),
elements(0),
capacity(0)
[code].....
The "Request" and "Free" functions are my engine's equivalent of malloc and free (or new and delete). I allocate a large buffer (16 mb), and through those functions I distribute the memory to where it's needed.
In this book, item 3 is about never treat arrays polymorphically. In the latter part of this item, the author talks about the result of deleting an array of derived class objects through a base class pointer is undefined. What does it mean? I have an example here,
Code:
class B
{
public:
B():_y(1){}
virtual ~B() {
cout<<"~B()"<<endl;
[Code] ....
This sample code does exactly what I want. So does the author mean the way I did is undefined?
I've got some functions and macros that I want to execute based on a string input that matches the function's name. I came across as this being a possible solution that I'd like to pursue IF it is possible to do. To clarify, I want to be able to look at a string and if the string matches the name of a defined function or macro then it will execute. Is there an effective way to do this (or is it even possible)?
It has to be pretty robust and dynamic given the project's purpose. Basically there's an input file that is being parsed and functions should execute if called upon in the file. I can't simply match strings to their corresponding functions in decision statements, as this isn't robust and isn't scalable.
I am having trouble with the array pointer and with the variables. I don't seem to have the pointer set up because the additional times the array is called it is empty. Also, if I don't use integers the program drops through. where I am going wrong?
Question is in the code
/*
NumClass
Main.cpp
*******************************************************************************************
*
* Design a class that has an array of floating point numbers. The constructor should accept an integer argument and dynamically allocate the array to hold that many numbers. The destructor should free the memory held by the array. In addition, there should be member functions to perform the following operations:
*
**Store a number in any element in of the array
[code].....
I 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] ....
I want to create a binary file based on some hex data :
Ex Input Hex :54313032202020303030
Out put like :6
I want to create a text-based game with C++, running on the console. I have made some other text-based console games.
Which is the most interesting text-based game to learn how to program for beginners?
I have this assignment where I have to create a map based hash table for a sparse matrix. The professor has provided some code and I'm supposed to fill in parts of it to make it work.
He has given us a class sparseMatrix which we need to provide a hash function for. This hash function is to be defined in a Class TupleHash which is inside sparseMatrix. I think I got that part down. What is really confusing me is what he has done with some typedefs.
For one of them I had to declare an unorderd_map that maps a struct Tuple on to the class template argument Object. I did that like so:
typedef unordered_map<Object,Tuple,TupleHash> HashTable;
The next typedef was given to me like so:
typedef typename HashTable::value_type valueType;
This is giving me a world of unintelligible error messages. This is how it starts.
In instantiation of 'struct std::__detail::__is_noexcept_hash<int, sparseMatrix<int>::TupleHash>':|
recursively required from 'struct std::__and_<std::is_default_constructible<sparseMatrix<int>::TupleHash>, std::is_copy_assignable<sparseMatrix<int>::TupleHash>, std::__detail::__is_noexcept_hash<int, sparseMatrix<int>::TupleHash> >'|
Ok I'm trying to create matrix of data that I can add values to based on a reading that I will get from a DVM. I'm using a 3d vector to do this. I need to keep track of the serial number, the day and within day I need to take two readings at different temps, this will continue for 7 days.
The rows of my 3d vector will be the days, the colums will be the serial numbers the depth will be the reading at the different temps.
What I need to do is compare the first element (days) and when it is greater then or equal to 4 I will perform calculations of the readings. So all I want to do is compare the first element of the vector, How do I do this?
Here is what I got
Code:
#include <vector>
typedef std::vector<double> Double1D;
typedef std::vector<Double1D> Double2D;
typedef std::vector<Double2D> Double3D;
#define HEIGHT 5
#define WIDTH 3
[Code]....
I'm writing a program in which I have to use a matrix to represent a file in code. because it's a file, the size of the matrix is undefined, and therefore the matrix has to be dynamic. I found out that my compiler doesn't like dynamic multidimensional arrays, so I was thinking of this matrix as a dynamic (monodimensional) array of other dynamic (monodimensional) arrays. My program (and thus this example) uses unsigned chars.
unsigned char variable=something;
unsigned char**matrix=new unsigned char*[lenghtOfMainArray];
for(int rowNumber=0;rowNumber<lenghtOfArray;rowNumber++)
{
[Code].....
I have two classes, productListType and buyerListType, that are each basically linked lists. To create the linked list for an object of productListType, I successfully wrote a non-class function createProductList to read the product data from a text file. The class definition for buyerListType has a data member productBoughtRecord that is of type productListType to aggregate the details of the products purchased by a particular buyer during transactions. I decided to make productBoughtRecord a pointer since the contents of this data member would wax and wane over the course of several transactions, depending on the amount and frequency of payments made by the buyer. I have provided a rough sketch of the class below:
class buyerListType
{
public:
setCustomerInfo( ....., productListType* p);
.
.
.
private:
productListType* productBoughtRecord;
.
.
};
I'm similarly trying to write a non-class function createBuyerList to load the record of customers from a text file. How do I determine what the value of the formal parameter p in member function setCustomerInfo is, in order to be able to set the data member productBoughtRecord? take into consideration that an object of class buyerListType would have multiple buyers with varying amounts of products purchased.
I'm trying to read a "pointer-based" maze .txt. The first letter in each row corresponds to the room letter...then the letters that follow are North node, East node, South node, and West node respectively. The asterisk indicates an empty room or not a valid option.
Here is what I have come up with, what is happening is after the file is parsed by read_maze it is calling my is_empty function indicating that there is no maze because it doesn't go into the else statement here.
I've attached a sample input file:
maze.txt (130bytes)
Number of downloads: 19
We can't assume the rooms will be in order alphabetically A - Z, We are expecting a maximum of 12 rooms and there is a space between each letter or asterisk.
void Maze::read_maze(string FileName){
string line;
ifstream inStream;
inStream.open(FileName.c_str());
int test = inStream.peek();
int i = 0;
if (!(inStream.fail())){
while (!inStream.eof() && test != EOF){
[code]....
i have to create a console based application in c language that can join and split bitmap images. the requirements of the application are as follows :
1. Split Image
Enter number of parts:
Enter source image path:
Enter destination folder:
2. Join Images (all images should be of same width and height)
Enter image path:
Join more Image (y/n):
3. Exit
Take care of following things:
- Application should show number of images processed while running.
- Acceptable Image format is BMP only.
- Application should give all the validations for correct image name, type, size, path, etc.
I need to create a program that prints a certain number of asterisks based on user input. The user inputs 5 and I want my program to output "*****". How would I do this in C? I've tried printf("%#**", myvariable) but this does not work it only prints "*".
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