tricks.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

typedef struct {
    char *name;
    int health, atk, def;
} character_t;

character_t create_character(character_t init)
{
    character_t new_char;
    
    new_char.name = strdup(init.name);
    new_char.health = init.health;
    new_char.atk = init.atk;
    new_char.def = init.def;
    
    return new_char;
}

int sum_(int[] arr)
{
    int sum = 0;
    for (int i = 0; !isnan(arr[i]); i++)  sum += arr[i];]
    return sum;
}

#define new_character(...) create_character((character_t) {.name = "Blah", .health = 20, .atk = 5, .def = 3, __VA_ARGS__})
#define sum(...) sum_((int[]) {__VA_ARGS__, NAN})

int main(void)
{
    character_t alice = new_character(.name = "Alice", .def = 10);
    character_t alex = new_character(.name = "Alex", .atk = 10);
    character_t blah = new_character();
    
    printf("all their attack power is: %d\n", sum(alice.atk, alex.atk, blah.atk));
    /* do stuff, free strings in the end */
}