Working on this one from the Jumping into c++ book. The book asks that I create a multidimensional array at run time based on user input and fill it with a multiplication table
My code compiles fine but throws an uninitiated error for p when I try and run it.
Code:
void multiDimentionalMultiplication(int x, int y, int z){
int ***p;
**p = new int[x];
std::cout << "Allocating array.
[code]....
I am trying to figure out the syntax to dynamically allocate a single dimension of a triple dimensional array. Basically i have a 2D array of structs. but each struct is an array (basically rows of the information). The rows of this structure need to be allocated dynamically, but the height and width of the overarching structure are static.
Basically: Struct * ts_FieldInfo[100][100] = new Struct[Class.returndataitems()];
so I have this code that dynamically allocates a pointer array increasing and removing elements of the array as its operated on.then it sorts and prints out the array when the user is finished operation on the array. i get this error message when running the program though.
"Unhandled exception at 0x0F474F98 (msvcr110d.dll) in Lab10_VarArray.exe: 0xC0000005: Access violation reading location 0xCCCCCCC0."
this is my code
#include <iostream>
#include <cstdlib>
#include "Header.h"
using std::cout; using std::endl; using std::cin;
int main(void) {
char op='x';
[Code]...
This is a homework assignment where I have to read a file into a dynamically allocated 2d array. The file format is
10
Jim 3.6
Jake 4.0
Will 3.0
Sara 3.4
Mike 2.5
Ellen 2.9
Melissa 3.9
Eric 3.8
John 3.5
Beth 3.9
where 10 is the number of students followed by the students and the gpa's. There is more to the program but I have not implemented it yet because I am getting a segmentation fault. The output I am getting when I print the array is
Jim 3.6
Jake 4.0
Will 3.0
Sara 3.4
Segmentation fault
I can see where the problem lies. If I raise value for row when I am allocating the rows of the array, all of the names print. I just do not see why I need to. From my understanding the row * sizeof(char*) should give me enough room for 10 entrie.
Code:
#include <stdio.h>
#include <stdlib.h>
void sort();
int main()
[Code] .....
I'm trying to dynamically allocate a standard array at runtime in the function of a class where the array is "owned" by the calling class. The calling class knows nothing about the array before it makes the call to create the array other than the datatype of the array. But the full array of data needs to be returned.
It appears that the pointer being passed makes a copy of the pointer on the stack and then when the function returns it pops it off the stack and the array is a memory leak because the pointer is once again a nullptr as it was before being passed and the array has not been deallocated with delete yet (as it should not have been).
(Edit:Unexpected value of MyArray being a nullptr instead of pointing to an array after returning from line 09.)
class Class1 {
void FunctionA() {
Class2 OwnedClass;
int* MyArray = nullptr;
int SizeOfMyArray = 0;
[Code] ....
I'm trying extremely hard to understand pointers and I have the basic concept down.. I feel as though my knowledge of dynamically allocated pointers and pointers in general is not enough to understand the logic behind what I'm trying to do. The problem is that the donations array must be able to accept any number of donations. I've made it do just that, but there is also an array of pointers which must each point to the same element in the donations array. The program works if I assign int *arrPtr[100] for example, but it does not work if I try to dynamically allocate it to accept the same number of elements for donations entered by the user. Here it's the snippet
#include <iostream>
using namespace std;
//Function Prototypes
[Code]....
I have created a database for music cds:
Code:
#include<stdio.h>
#include<stdlib.h>
#define array
typedef struct cd_database
[Code]....
When I am using malloc instead of arrays the code is not working properly after exit. I have tried alot but can't came up with a way
I have an abstract based class and three derived classes. I also have a templated hash table class(using chaining as my collision resolution method, an array of stl lists), and a class to parse commands from a file, this also holds the instantiation of the hash table. My question is that since my command parsing class's constructor instantiates the hash table in the main driver(unable to modify) how can I make this dynamically allocated using data from the file?
template<class T>
class hashTable{
public:
hashTable(int size);
~hashTable();
[Code] .....
Do you have to allocate memory(malloc) for an array of structs? Example:
Code:
typedef struct{
char * name;
}First;
struct name{
First fname;
};
struct name Names[10];
#include <iostream>
using namespace std;
int main() {
int elm = 0;
int size = 0;
int *array;
[Code] ....
I'm making some multi-threaded program, but thats not my problem as i've done that already. I have a class with user-functions containing a structure which then contains a two dimensional array for each user with 25 elements. So I dont want to limit the user and make the array for example with just 10 rows, but allocate the needed memory to match the amount of 'users' a potential user of my program would want. The problem is, that i know how i should allocate it using 'new int' but it just doesnt work ! It gives an error:
Error: no operator "=" matches these operands
UserStuff.h:
struct userDataStruct {
bool* isAdmin;
[Code]...
Then, in some completely other class function inside the file mentioned above: (I know i could do a function in CUsers class which could allocate the memory, but I have this function which is used for some other things and it already has the amount of max users
void OtherClass::somefunction(maxusers)
{
// This gives an error: Error: no operator "=" matches these operands
curUsers->uData.userNumbers = new int*[maxusers]; //maxusers is the int variable of max users specified by the client
// However this doesn't
for( int i = 0 ; i < maxusers ; i++ )
curUsers->uData.userNumbers[i] = new int[25]; // 25 columns, this doesnt give any error
}
I'm not really sure what I'm doing wrong. Doing this in some function from CUsers class works (without curUsers-> or with, doesn't give any error) but doing it from some other class's function doesnt.
I want to be able to dynamically allocate and index an array like the following: vv2d[1][2].x and vv2d[1][2].y. In order to accomplish that I have chosen to use a std::vector of a std::vector of a 2D point class.
Code:
/// Here is my templated version of a 2d point class which I have adopted from
/// one by Alexander Chernosvitov, Function Graphics, 2001 (see ogview.h)
/// http://www.codeguru.com/cpp/g-m/opengl/article.php/c5581/Function-graphics-in-3D.htm
template <typename T>
[Code]....
Boundary violation occurs as soon as vv2d[1][0].x is encountered. I believe the problem is my inability to dynamically allocate the size of the (primary) typedef vector. However, eliminating the typedef for the following does not change the result. Further examination shows the vv2d[1][0] size and capacity to be 0.
Code:
vector<vector<CPoint2D<double>>> vv2d;
vv2d.resize(3);
vv2d[0].resize(3);
I have to allocate memory for an array of structures, and my structure looks as following:
Code:
typedef struct {
char *name;
Uint *start_pos;
Uint len;
}
example_struct;
And now I want to allocate memory, for a variable number (so an array) of example_struct, so I first do:
Code:
example struct *all_struct;
int total_num = 3;
//will be set somehow, but for the example I set it on 3 all_struct = malloc (sizeof(example_struct) * total_num);
And now, as far as I now, I will have to allocate for each field of the structure memory, in order to be able to use it later. But I have problem at this point, a problem of understanding:
- I just allocated memory for 3 structures, but don't I have to allocate then memory for each structure separately, or can I just now allocate the fields like this:
Code: all_struct[0].name = malloc.....
But if yes, why the hell this works...
I have a multidimensional array that runs parallel with a string array
Lincoln 120 300 400
Parks 100 500 250
Shakespeare 0 30 50
Ghandi 250 100 40
Ashe 300 50 175
Rodriguez 87 118 320
Curie 284 0 112
I need to sort this and I know how to do it. But I need to sort it again with the highest value in the first row and keep all information in that row paired with the name . So
Lincoln 120 300 400
Parks 100 500 250
Parks 100 500 250
Lincoln 120 300 400
I need so swap this whole rows. I'm using dynamic array. So my question is Do I have to do a bunch of temps to move them? Or is there a way to move the whole int array row as a single unit?
Problems :
1) Is there any way so that i can use "X" and "O" char instead of 9 and 0 int.?? I also tried to use enum but was only able to print out -1 for 'X' and 0 for 'O'...
2) if player - 1 choose field 2 . and player - 2 chooses field 2 .. how can i show error and ask for another input ?
3) is there any short coding trick for int check_result(); ?
Code:
#include <iostream>
#include <string>
#include <cstdlib>
using namespace std;
[Code] ....
What is the correct method of declaring pointer to multidimensional array
Code:
int array[3][4];
int *p = array;
The above code works but it shows warning. Is it an invalid way of using the pointer? the array is an address then why am i getting warning?
I'm trying to pass a two-dimensional array to a function. The function is defined as: long foobar(char foo[][CONST]); I have to create that array dynamically. Currently I do that this way: char* bar = new char[count * CONST];
But when I'm trying to pass the array I get a type conversion error. I tried a lot of different ways to pass the pointer and/or to allocate the memory, but apparently I didn't find the right way or combination of definition, allocation, casting and calling.I cannot change the definition of the function, which (IMHO) is pretty stupid. :(
I have put aside C++ for a while. And I am back to it.
I forgot how to return a 2 dimensional arrays from a method?
Code:
Node** GetNodeMap() const { return m_Nodes; }
private:
Node m_Nodes[60][60];
How can I achieve that?
I have initialized a multidimensional array eg char fruit[5][10]...Then I would need to read in 3 words with spaces in between from user and store in fruit[5][10] e.g "pear apple orange"
The thing is that after typing orange, when I press Enter it still prompts me to enter more characters. How can I end the scanning of characters after orange ?
I have a 3-dimensional matrix(3,3,3) and want to write it to a file. I have the code for parsing it in a compatible for matlab format. But at this point i want to use a pointer to do the same thing.
Code:
#include <stdio.h>
#include <stdlib.h>
int main() {
const int dimx = 3, dimy = 3;
int i, j;
unsigned char a[3][3][3] = {
[Code]...
If it is a 1-dimensional array i can understand the logic.
Code:
int val[7] = { 11, 22, 33, 44, 55, 66, 77 } ;
int *p;
p = val[0];
for ( int i = 0 ; i <= 6 ; i++ )
[Code]...
I know how to find a specific number in a multidimensional array, but I don't know how to have a specific number and find its coordinates.
View 2 Replies View RelatedIn 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] .....
In the code that I am working on I am generating random numbers and assigning them a 2d array. But when I output the array in a separate nest of for loops the values are incorrect, but if I output the array in the same nest of for loops the values are correct
int spot[4][4];
int range[] = {1,16,31,46,61}, held[4];
void Generate() {
for (int y =0; y<=4; y++) {
for ( int x =0; x<=4; x++) {
spot[x][y] = (range[x] + rand() % 15);
[Code] ....
For a rather complex and strange reason that I won't explain right now, I need to have this going on in my program.
class FVF{
private:
vector<vector<float>> data; //Contains fvf data for Direct3D stuff
public:
[Code].....
The FVF allows this Model3D class to also be compatible with file handling methods I've got, but here's the problem. D3D buffers require an array to feed them the information, and I know that for a single dimension of vector I can use vec.data(), how to do this for multiple dimensions.
I think the best Idea I've got so far is to set the vector within the Model3D class as a pointer, then I can union it with a float pointer... Once I can guarantee the information is correct and complete, manually transfer the contents of the vectors into the float pointer.. (The union is to reduce memory needed instead of having the data repeated in vectors and arrays)
how I could just pass these as arrays?
I am trying to unroll the inner i and j loops within this multi-dimensional array which spits out a block image. Unfortunately, the image does not match the color of the original image probably because filter->get(i,j) gets altered in a way that I don't want it to.
double
applyFilter(struct Filter *filter, cs1300bmp *input, cs1300bmp *output) {
long long cycStart, cycStop;
cycStart = rdtscll();
output -> width = input -> width;
output -> height = input -> height;
[code]....
void printMatrix(int x[][]){
cout << "Matrix " << x << ":" << endl;
for(int r=0;r<rows;r++){
for(int c=0;c<colums;c++){
cout << x[r][c] << " ";
} cout << endl;
}
}
Error: declaration of 'x' as multidimensional array must have bounds for all dimensions except the first
How can i use multidimensional array with unknown bounds?