Code:
Int** d = malloc( ROWS * sizeof(int*));
for (i = 0; i < ROWS; i++)
d[i] = malloc(COLS * sizeof(int));
fx(d);
My question is, in a function declaration, why do I not have to specify the number of columns. How is this different than when I pass a static 2D array to a function, in which I must declare the function parameter with the number of columns.
Code: void fx(int d[][COLS]);
VS.
Code: void fx(int **d);
I made a resize function for my dynamic array template class that goes as follows. Note that the private member variables are T* arr, unsigned used, and unsigned cap.
template <class T>
void darray<T>::resize(unsigned size) {
if (size > cap) {
T* temp_arr = new T[size];
[Code] ....
Whenever I use this function to increase the size of the array, it will work the first time I need to use it, but after that, Visual Studios will trigger a breakpoint at line 14, and if I continue past the breaks, I eventually get _CrtIsValidHeapPointer(pUserData) assertion failure.
I am trying to pass a dynamic array to a function which will:
- Copy the contents of the array to a temporary dynamic array
- Change the array passed in to one size bigger
- Copy the elements from the temp array back into the newly changed array
- Insert an item into the last spot of the array
Here is my code:
#include <iostream>
using namespace std ;
void make_array ( int Old [] , int & old_size , int toInsert ) ;
void zero_array ( int arry [] , int arry_size ) ;
void print_array ( int arry [] , int arry_size ) ;
[Code] .....
The output seems like a memory address but is just a very large number, what have I done incorrectly to cause this?
code:
/part of main function
int *A=NULL;
//load from file
load_from_file(A, &next);
printf("next=%d
",next);
getchar();
printf("A[%d]=%d
",0,A[0]);getchar();//here program crashes
}
[code]....
I initialize array A with NULL in main, and I "load" it with elements from a file. The code without function is working. But when I tried to use a function as above, my array crashes!!!
I'm writing a program that will implement BubbleSort and MergeSort and time them as they sort a dynamic array with N elements. These are the instructions on what my main.cpp file should do.
main.cpp
Include all needed libraries for timing and random number generation while the number of element, N, is less than 100001 repeat the following.
create an array with N (initially 10) random elements
sort the same array with Bubble and Merge sort
time how long it takes each algorithm in microseconds (see example below)
Increase N by a factor of 10 (N *= 10)
Hint: you may want to put your merge sort object on the heap and delete it with every iteration of this loop
And this is what I have so far for my main.cpp
#include <iostream>
#include <sys/time.h>
#include <ctime>
#include <cstdlib>
#include <stack>
#include <iomanip>
#include "BubbleSort.h"
//#include "MergeSort.h"
[Code] .....
One of the errors that I'm running into is that I'm not sure how to correctly call the function I think?
my program is just counting the maximum of the array, however, I'd like to do that with the dynamic array (with pointers).
Code:
#include <stdio.h>
#include <stdlib.h>
void ArrayScan(int n, int *h);
void ArrayMaximum(int n, int *h, int x);
int main()
}
[code]....
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 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'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 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]....
i need a function that will work for both dynamic and static implementations of a function to get the transverse of a matrix. so far, i have this
Code:
matrix transpose(matrix m)
{
int row, col;
row = m.com_dim;
col= m.row_dim;
}
[code]....
this works well with my static implementation, but when i try it in dynamic it gives me errors. the function has to be the same for both dynamic and static implementation
But it can the other way around
Code:
static_Array= dynamic_Array;
dynamic_Array = static_Array;
The second statement works and i'm able to print out both arrays with equal values but with the first
[code] static_Array = dynamic_Array;I get incompatible types in assignment of 'int*' to 'int [7]' is the error I get [/code]
Is this considered a memory leak?
Polygon* create_square(const Vector2d& position, const RGB& colour, const std::string name) {
// Polygon, Vector2D, RPG and Vertex2d are structs with public data members only
Polygon *temp = new Polygon;
temp->name = name;
temp->colour = colour;
temp->position = position;
temp->vertices = new Vertex2d;
return temp;
}
I need to design an interface(a function prototype) that takes an argument which is used to pass information.
The information can be passed by independent modules and third party softwares and hence can vary today and in future.
Basically, the function interface(arg1, info)caters a niche service to many independent applications and needs to process based on requirements passed by applications in the argument(info, in example).
I am looking for a design pattern for the function parameter - info.
Should I use a void pointer that can be casted to respective application specific class in the function ? will this be a good C++ design ?
or should I take this parameter to be a pointer to a generic abstract class that points to the respective application specific specialization ?
Do we have some design pattern to address this so as to handle other unforeseen challenges ?
Can I return a non-dynamic local address of a var from a function?
int* func(int m){
m=1;
return m;
}
My compiler giving warning but compiles and returns add but My tutor handout says it will not compile...!!! she used array in func and returned arr[m]
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'm trying to create a function that uses dynamic allocated arrays instead of vectors because I want to see how they work. Basically, this function asks the user to input how many people they are going to enter followed by their name; then, they enter how many of these people want to register for an ID followed by their phone #.
For example:
"How many customers will you like to enter? " 3 //user inputs 3
Bob Allen //user input
Ellen Michaels //user input
Jane Andrews //user input
[Code].....
I remember in C++, when a dynamic array is allocated, the size of this array is stored right before the array in memory. Therefore compiler knows exactly how long, when this array is deleted.
Do all compilers store the size this way? Is it a safe method to get the size of a dynamic array?
Here is a example code, it works fine on Visual Studio 2012.
#include <iostream>
using namespace std;
class dummy {
public:
dummy() {
cout<<"dummy created"<<endl;
[Code]...
So this is the code I have so far, I didn't know it had to be a dynamic array so how would I Utilize dynamic array allocation to size the modal array
#include <iostream>
using namespace std;
int main() {
const int arraySize = 25;
const int patternSize = 10;
[Code] ....
I need to create dynamic array or map. for example
CString *a1;
CString *a2;
CString *a3;
it minimized to using for loop.
for (int i=1;i<=3;i++) {
CString s="a"+"itoa(i)"
CString *s;
}
Something like this. its same as map concept.
I need to confirm that this problem cannot be solved without a pointer. Namely I need to read the rows and columns number from the user cin >> m, n and then use to declare an array int A[m][n];
However as m and n are not constants I am not able to do that. Is there a workaround? The following is the solution I came with BUT using a pointers which should be not the case.
// solution with using pointers as "int A[m][n]" does not work for me!!!
void TwoDimensionalArrayFunc(){
int m = 0;
int n = 0;
// instruct the users to enter array dimensions
cout << "Please insert value for m:";
cin >> m;
[Code] ....
arrays with dynamic sizes. That being said, I'm working with a simple code which seems to work just fine, my only concern is that once I display the 'char array', not only displays the user's inputs but some extra data, symbols and what not.
why, if to my understanding the first user's input already sets the size of the array
#include <iostream>
#include <iomanip>
using namespace std;
[Code].....
I need to write 2 functions:
1. MyMalloc
2. MyFree
___________________________
I have a 1000 bytes global array (which did not dynamic allocated).
I need to make "dynamic allocation" from this array.
For example - MyMalloc(50) ---> The program will allocate 50 bytes OF THE ARRAY'S SIZE.
------
MyFree(pointer) ---> I need to check if the pointer is in the array and free the space.
It should be managed by blocks. The array should also contain the manage variables (for me).
I am trying to figure out copy constructors for a dynamic array and I am definitely missing something. If I go into the copy constructor routine during debug, the values appear to be correct but they don't percolate up to the newly created object. I'll post a portion of the code below:
Code:
// include header files for the classes that are being used
#include "stdafx.h" //
NOTE: THis reference must be added to all cpp files in Visual Studio Express 2013
#include <iostream>
#include <string>
#include <cstdlib>
#include <map>
using namespace std;
const int ARRAY_SIZE_DEFAULT = 32;
class vectorOfInt {
public:
[code]....
The size of c is 0. Values of a were not copied to c, although they appear to do so within the copy constructor routine.
Code:
public void dam_data_setup() {
// fill list
damgtype.Add( den1);
damgtype.Add( den2);
damgtype.Add( da1);
damgtype.Add( da2);
damgtype.Add( db1);
damgtype.Add( db2);
[Code] .....
This is a genetics program and is to parse the source array and write all possible combinations to a new array. All sections but dilute work correctly. For some reason the dilute's Boolean is not testing true when it should. This is causing data corruption.
I have a little problem with one of my functions. The function purpose is to get a number (n) and create an array (size n) with pointers to strings (each string length is 20 chars) and i don't know why but during the debugging i get a <bad ptr> message and this message :
CXX0030: Error: expression cannot be evaluated
This is my function:
Code:
char** getlist(int n) {
int i=0;
char **arr;
arr=(char**)malloc(sizeof(char)*n);
if (arr==NULL)
[Code] ....