All Questions
Tagged with pointer-to-pointer arrays
39 questions
0
votes
3
answers
123
views
Accessing information on a 2d array with a double pointer in a struct (C)
In trying to understand pointers, I created a M[x][y] array, a pointer to said array *p_M[x] and a pointer to said pointer **d_p_M. The first pointer points to the first element of a row in the array ...
2
votes
3
answers
158
views
Converting to char*** from char* [2][2]
I have the following variable
char* a[2][2] = {{"123", "456"}, {"234", "567"}};
I wanted to refer it using another variable. While the cast works, accessing ...
- 89
0
votes
0
answers
63
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Why do we use a single pointer rather than a double pointer to pass an array to a function? [duplicate]
Why not double pointer to take an array?
I'm having a bit of problem understanding why an array isn't passed as a double pointer (a pointer to a pointer) since the array name itself is a pointer (...
- 11
1
vote
3
answers
63
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How does this code allocate memory and why does it fail to write to the allocated memory?
Why does the code below compile successfully but fail to write memory other than address 0? (compiled in dev-cpp 6.3)
#include <stdio.h>
#include <stdlib.h>
void alloc_arr(int **d_ptr);
...
- 11
1
vote
1
answer
126
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Is it better to store a 2D image in a flat array or in an array of arrays?
I have two options.
receiving and processing pixel data in a flat array.
If I choose it, I have to use single pointer.
I have to use this code in every repeated pixel data process.
int getIndex(int ...
- 11
0
votes
1
answer
56
views
Getting Null iterate through to next element of array using pointers
#import<stdio.h>
#import<stdlib.h>
typedef struct Video {
char *name;
int unique_views;
} Video;
typedef struct Viewer {
char *username;
Video *watched_videos;
int ...
0
votes
2
answers
530
views
Incompatible pointer type pointer to array and double pointer to array
So i am new to programming and i have this program that i have to write, it has an array of integers and i have to pass it to a function with a pointer and then with a double pointer.
After i wrote ...
- 13
-1
votes
1
answer
56
views
C -- pointers to pointers VERSUS array of pointers
In C, why can't I write:
char **expectedPINs01 = { "0", "5", "7", "8", "9" };
Cause I got:
warning: initialization of ‘char **’ from incompatible ...
- 25
0
votes
3
answers
794
views
print each char of string array with double pointer in C++
The program is expected to print each char of the string array.
#include <iostream>
#include <string>
using namespace std;
int main()
{
const char* numbers[10]{"One", "...
- 171
-2
votes
2
answers
473
views
Pointer Pointer leads to Segmentation Fault in C
Why can I create an array of pointers and dereference its (pointer-)elements.
int a = 1;
int* arr[1];
arr[0] = &a;
But cannot do the same with pointer to pointers:
int** arr2;
arr2[0] = &a;
-...
- 19
0
votes
1
answer
104
views
C - Writing a struct into a 2D array causes Segmentation Fault
I'm trying to write a program that reads a text file into a 2D array of structs, but trying to put a struct into that array causes the program to crash.
Here's the program
ppm.c
#include "ppm.h&...
0
votes
1
answer
180
views
dynamic array of strings, but i get heap corruption detected
I try to make a dynamic array of char pointer, what means does pointers can be a dynamic memory too, so in the code above I try to allocate one size to the array and in him, allocate to the first ...
0
votes
1
answer
100
views
Double pointer with array in another function
I have to create a program that has an array of costumers (structs that contain name, code and documentation) and functions to insert, remove and list all of them in order of code. I'm not ...
- 11
1
vote
2
answers
2k
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C++ Getting neighbours of a cell in a grid, -1x throwing null exception when checked if != NULL
recently moved from C# to C++ so I'm new to pointers and references and so on.
I've a pointer-to-pointer array declared like this
enum Type
{
Void,
DeepWater,
Water,
... etc }
Tile::...
- 301
2
votes
1
answer
98
views
Logic behind calling function by using "Pointer to a function"
Suppose there is a pointer f declared to some function say int foo(int) as :
int (*f)(int)=foo;
While mentioning about calling foo() function by using this ponter which is passed as argument to some ...
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