An example of dynamic arrays in C

HelloDynmaicArray.c

/**
* @brief: Shows a minimalistic example of dynamic arrays.
*
* @author pavl_g.
*/
#include<stdio.h>
#include<stdlib.h>
#include<string.h>

typedef struct {
    const char* username;
    const char* password;
} User;

static inline User* getUserFromCredentials(const char* username, const char* password) {
    User* user = (User*) calloc(1, sizeof(User));
    user->username = username;
    user->password = password;
    return user;
}

static inline void addUser(User** users, User* user, int index) {
    users[index] = user; // jump to a new user
}

int main() {
    
    void** users = (void**) calloc(1, sizeof(void*));
    
    User* bishoy = getUserFromCredentials("Bishoy", "BPass");
    User* pavly = getUserFromCredentials("Pavly", "PPass");
    
    addUser(users, bishoy, 0);
    addUser(users, pavly, 1);
    
    printf("%s \n", ((User*) users[0])->username);
    printf("%s \n", ((User*) users[1])->username);

    printf("%s \n", ((User*) users[0])->password);
    printf("%s \n", ((User*) users[1])->password);
    
    return 0;
}

Output:

Bishoy 
Pavly 
BPass 
PPass