So I need to write some code that performs partial integration. I have a numerical integrator schematically represented by double integrate(double (*func)(double)); and suppose it works properly, i.e. for a function double f(double x), integrate(f) gives the right result. What I have instead, however, are functions that look like double f(double x, double y); and… Read More Creating function pointers in C with arguments

#include <stdio.h> void test1(){ printf("test1\n"); } void test2(){ printf("test2\n"); } void test3(){ printf("test3\n"); } void test4(){ printf("test4\n"); } void (*hv_ptr[2])() = {test1,test2}; void (*dev_ptr[2])() = {test3,test4}; void (**ptr[2])() = {hv_ptr, dev_ptr}; int main() { ptr[0][0]; ptr[0][1]; ptr[1][0]; ptr[1][1]; return 0; } I have declared the array of pointers to function pointers. But with this code,… Read More Invoking function from the 2d array of function pointers

I wanted to test a my idea about function pointers. I wrote a test but it doesn’t work(causes a Segmentation fault). Here is my test simplified: #include<stdlib.h> void a(){} void b(){} int main(){ size_t s=0; char* p1=(char*)&a; char* p2=(char*)&b; while(*p1++==*p2++) s++; void (*o)(); char* c=malloc(s); while(s–) *(c+s)=*((char*)&a+s); o=(void(*)())c; o(); return 0; } The code should… Read More Function pointer assignement and typecast

I am implementing a sort of a linked list, where each node has a key, a value, and the next node. I have a function called getVal, which should take in a key, and a linked list, that returns the value corresponding to that key. The thing is, I don’t know the datatype of the… Read More Function that takes in unknown datatype c

I have the following structure definitions: typedef struct S_t S_t; struct S_t { float *s_ptr; uint32_t ns; }; typedef struct p_t p_t; struct p_t { int32_t pID; float pVal; }; typedef struct pr_t pr_t; struct pr_t { S_t *S; int (*TrimS)(S_t *TS, int sSize); p_t *TP; }; I also have the following function defined: int… Read More How to access the value of a struct member which stores return value of a function pointer?

In C, one can declare pointers to functions like that: void (*Func1)(int) I believe that I’ve understood what this means (in this case, a pointer to a function which returns void and takes an int as parameter) and how to declare and use such pointers. However, I now have come across declarations like the following:… Read More How to understand that function / pointer declaration?

void qsort(void *base, size_t nitems, size_t size, int (*compar)(const void *, const void*)) Is there a way to pass, let’s say strcmp to qsort without making a helper function? I was trying to do: qsort(…, (int (*) (const void*, const void*) (strcmp))); >Solution : Your attempt at the cast simply has a misplaced right (closing)… Read More Casting function pointer arguments without a helper function

I have a midterm in Saturday, so our teacher gave us the previous year’s midterm to help. So there is a problem that I have trouble to understand. The question is ‘fill the question marks so that program outputs the string ‘accioccium’. For who do not want to spend on solving, the answers are 1,2… Read More type + pointer array size + paranthesis meaning in syntax

What I would like to do is : a simple function "register_function" allowing a user to indicate a callback function to call (that this user has implemented) when calling that function with "call_callback", to be able to pass arguments like a buffer for example Here is my code: static void (*callback)(int *buffer, int size) =… Read More How can I register a simple callback function and pass arguments to that function?

I’m trying to make an array of functions so I can call functions from the array with an index. I can’t seem to figure out the parentheses, asterisks and brackets to create this array of functions. Here is what I have: void Game::getPawnMoves(int position, bool color, Move ** moveList) { … } typedef void (*GetMoveFunction)… Read More How Should I Define an Array of Pointers to Functions in C++?