Error trying to access an array element

Question

How do I make the execution of mine loop generates a registration code automatically?

Error on line 36 - 'book[i]. Cod = i;' [Error] subscripted value is neither array nor Pointer nor vector

Objective since code: register 5 books with information of the same and generate a code automatically for each generated book.

Current code:

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

/*Definindo tamanho*/
#define TAM 5


int main(void) {


    /*--Criando a struct--*/
    struct ficha_do_livro {
        int cod;
        char nome_da_obra[50];
        char nome_do_autor[50];
        char nome_da_editora[50];
    }livro;


    /*--Cadastro do Livro--*/
    int i; 

    for (i = 0; i < TAM; i++) {

        printf("\n---------- Cadastro dos Livros -----------\n\n\n");

        livro[i].cod = i;
        printf("Insira o nome da Obra: ");
        fflush(stdin);
        fgets(livro.nome_da_obra, 40, stdin);

        printf("Insira o nome do autor: ");
        fflush(stdin);
        fgets(livro.nome_do_autor, 40, stdin);

        printf("Insira o nome da Editora: ");
        fflush(stdin);
        fgets(livro.nome_da_editora, 40, stdin);

    }
}

Answer 1

Tam some errors in the code. The one that appears is that is trying to access an element of a array in something that is not a array. You declared a structure, and a variable with her type, but there only fits a single element. If you want to put several elements you need to put in the syntax you want this, indicating how many elements this variable will have. Then this error will disappear. But it will make other mistakes since the other members of struct after the code also need to be accessed by the index of the array, then said put the i there also.

Pay close attention because I have removed a lot of things that were not needed in this code, and packed up some things that make it more efficient. Yes, even the comment is not necessary because it says an obviousness, comments were not made for that. Don’t use things you don’t know what it’s for.

#include <stdio.h>

#define TAM 5

int main(void) {
    struct {
        int cod;
        char nome_da_obra[41];
        char nome_do_autor[41];
        char nome_da_editora[41];
    } livros[TAM];
    for (int i = 0; i < TAM; i++) {
        printf("\n---------- Cadastro dos Livros -----------\n");
        livro[i].cod = i;
        printf("Insira o nome da Obra: ");
        fgets(livro[i].nome_da_obra, 40, stdin);
        printf("Insira o nome do autor: ");
        fgets(livro[i].nome_do_autor, 40, stdin);
        printf("Insira o nome da Editora: ");
        fgets(livro[i].nome_da_editora, 40, stdin);
    }
}

Behold working in the ideone. And in the repl it.. Also put on the Github for future reference.

Answer 2

You need to use an array of structures.
Obs. not tested.

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

/*Definindo tamanho*/
#define TAM 5

int main(void)
{

  /*--Criando a struct--*/
  struct ficha_do_livro
  {
    int cod;
    char nome_da_obra[50];
    char nome_do_autor[50];
    char nome_da_editora[50];
  } livro[TAM]; // <-----------------------

  /*--Cadastro do Livro--*/
  int i; 

  for (i = 0; i < TAM; i++)
  {
    printf("\n---------- Cadastro dos Livros -----------\n\n\n");

    livro[i].cod = i;
    printf("Insira o nome da Obra: ");
    fflush(stdin);
    fgets(livro[i].nome_da_obra, 40, stdin); // <---------------

    printf("Insira o nome do autor: ");
    fflush(stdin);
    fgets(livro[i].nome_do_autor, 40, stdin); // <-----------------------

    printf("Insira o nome da Editora: ");
    fflush(stdin);
    fgets(livro[i].nome_da_editora, 40, stdin); // <---------------------

  }
}