Can I use strings within an array to name struct variables using concatenation, macros, or similar?

Question

I have an array of animal names in the order that I intend to create each struct 'animal' and store it in farm_animals, a struct of animals.

typedef struct ani animal;

animal* farm_animals[128] = {0};

Although the below code is totally invalid, I have included it here to show exactly what I have thought of achieving in practice. I want to declare a variable of type animal corresponding to a string literal in the array, and then somehow use that literal as the name of the animal and store it in an array.

char* animal_names [] = {"Oliver", "Marcus", "Mike", "John", "Tom", "Daisy", "Lilac", "Rose", "Jim"};

    for (int i = 0; i < 9; i++) { 
        animal animal_names[i];
        farm_animals[i] = animal_names[i];
    }

I have researched and found many other similar posts which conclude that since C is a compiled not interpreted language, it is not possible to name a variable with the value of a string. However, I was wondering if it is possible to concatenate the string name with a suffix (like the index number) to create an entirely new 'string name' to refer to the animal. I have also though of a macro using an array or the same animal_names array, but this has not been clear for me to implement as a beginner.

I think this sort of idea in C is far-fetched, but I really wonder if there is a way to name these structs using a for loop and array of names, rather than manually creating 100+ structs.

Answer 1

Yes, it is not possible to dynamically name variables in C. If I understand correctly, you want to create an animal type corresponding to a string and then name it that name.

The advantage with using structs is that you can combine related/relevant data into a single variable (the struct) – which itself is a collection of multiple variables.

I would suggest organizing something like this:

typedef struct animal {
  char[20] name;
  char[20] type;
} animal;

You can replace the character array with a pointer to the string (char*) as well. Also, if you know the type of animals that could be created you can instead create an enum like this:

#define MAX_NAME_LEN 20
#define MAX_NUM_ANIMALS 10

enum animalType {
  LION,
  ELEPHANT,
  FALCON,
  PARROT
};

typedef struct animal {
  char[MAX_NAME_LEN] name;
  enum animalType type;
} animal;

int main(void) {
  animal listOfAnimals[MAX_NUM_ANIMALS];

  listOfAnimals[0].type = PARROT;
  listOfAnimals[0].name = "my parrot";

  return 0;
}

So, instead of making 100+ structs, you would make an array of structs and store the type of animal as a data member. Then you could use some mapping mechanism or conditional logic to assign these types to the struct variables as per your needs.