I was porting some older high-speed C++ code to C#, and the existing code made use of a pointer-based double-indirection pattern like this (written here in a C# syntax), using the stack as efficien...

Suppose I have an array of pointers to char in C: char *data[5] = { "boda", "cydo", "washington", "dc", "obama" }; And I wish to sort this array using qsort: qsort(data, 5, sizeof(char *), comp...

I am having trouble understanding how to assign memory to a double pointer. I want to read an array of strings and store it. char **ptr; fp = fopen("file.txt","r"); ptr = (char**)malloc(sizeof(...

Please consider the following code: #include <stdio.h> #include <stdlib.h> #define NUM_ARRAYS 4 #define NUM_ELEMENTS 4 #define INVALID_VAL -1 int main() { int index = INVALID_VAL; ...

I was looking at https://en.cppreference.com/w/cpp/language/reinterpret_cast and I noticed that it specifies the legal types we can always cast to: byte* char* unsigned char* But I did not see ...

Please find the code snippet as shown below: #include <stdio.h> int My_func(int **); int main() { int a =5; int *p = &a; My_Func(&p); printf("The val of *p is %d\n&quot...

I'm a COBOL programmer , and my latest project is to connect a COBOL application to a SQLite3 database. I have been following this guide, and their solution is exactly what I would need in my COBO...

Simple question here: is there any way to convert from a jagged array to a double pointer? e.g. Convert a double[][] to double** This can't be done just by casting unfortunately (as it can in pl...

I'm almost there but I can't quite understand how to convert unsigned char ** to a cv::Mat I know that the .data part of a cv::Mat is uchar* I'm using a function that returns and image in the ...

Imagine you have a class defined as follows. public class SomeClass { public Manager m { get; protected set; } public SpecialData data { get; protected set; } //More methods and member code he...

I have to write a function which takes in 2 double pointers (both to char type). The first double pointer has a string of query values and the 2nd one has stopwords. The idea is to eliminate the st...

I wanna use double pointer and I tried to declare like this. NSString **a; but, Xcode showed me the error "Pointer to non-const type 'NSString *' with no explicit ownership" and it couldn't be c...

In C, I am using a char ** to hold a series of strings. Here is my code: char ** c; //now to fill c with data ???? //cannot change: printf ("%*s%s", 0, "", *c); while (*++w) printf (" %s", *c);...

I am trying to get the number of rows and columns of a 2D Array from a double pointer pointed to the array. #include <stdio.h> #include <stdlib.h> void get_details(int **a) { int ro...

I want to a member variable, which is a double pointer. The object, the double pointer points to shall not be modified from outside the class. My following try yields an "invalid conversion from ...