printing memory garbage inside the vector

Question

Good afternoon guys, I’m starting to learn C in college, I have a job to do where I must create a code to register 5 different books (name, author, publisher) and generate a code automatically. The code should have a menu for the user to choose the option you want (0 quit, 1 register new book, 2 view books already registered). Well, my problem is in item 2 of my menu, at the time to show the user the books already registered, if I register the books they appear normal, however if I choose the option to show the books already registered not having any book registered still appears memory garbage in 2 entries of my vector, the vector has size 5, the problem is occurring only in the entries 1 and 2, the entries 0, 3 and 4 are appearing "The entrance [x] is empty!" as it should.

I wonder if someone can help me fix this and explain to me why this is happening, and only in 2 entries, follows below my code.

Thanks des de ja.

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

struct produto
{
    int codigo;
    char nome[51];
    char autor[51];
    char editora[21];
};

int aleatorio ()
{
    int i;
    int x;
    int codigo;

    srand(time(NULL));
    x = rand() % 9999;
    codigo = x;

    return codigo;
};

int main()
{   
    setlocale(LC_ALL, "Portuguese");
    struct produto livro[5];
    int opcao;
    int tamanho;
    int i;
    int x;
    int cod;
    char name[51];
    char author[51];
    char publisher[21];

    i = 0;
    x = 0;
    opcao = 3;

    while(opcao != 0)
    {
        printf("\n\n\n");
        printf("\t Escolha uma das opcoes: \n");
        printf("\t 1 - Cadastrar novo livro \n");
        printf("\t 2 - Visualizar livros cadastrados \n");
        printf("\t 0 - Sair \n");
        printf("\n\n\n");
        scanf("\t %d", &opcao);
        system("cls");
        switch(opcao)
        {
            case 0: // Encerar
                system("cls");
                exit(0);
                break;
            case 1: // inserir novo cadastro
                if (i == 5)
                {       
                    printf("\t Sistema de cadastro lotado. Não é possível armazenar mais informações! \n");
                    system("pause");
                    system("cls");
                    break;
                }
                else
                {
                    printf("\t Insira o nome do Livro: ");
                    scanf("%s", &name);
                    strcpy(livro[i].nome,name);
                    printf("\n");
                    fflush(stdin);

                    printf("\t Insira o nome do Autor: ");
                    scanf(" %s", &author);
                    strcpy(livro[i].autor,author);
                    printf("\n");
                    fflush(stdin);

                    printf("\t Insira o nome do Editora: ");
                    scanf(" %s", &publisher);
                    strcpy(livro[i].editora,publisher);
                    printf("\n");
                    fflush(stdin);

                    cod = aleatorio();
                    livro[i].codigo = cod;
                    printf("\t O codigo do livro registrado e: %d \n \n", livro[i].codigo);
                    printf("\t Livro cadastrado com Sucesso! \n");
                    system("pause");
                    system("cls");
                    i++;
                    break;
                }
            case 2: // mostrar todas as entradas
                for (x=0; x<=4; x++)
                {
                    tamanho=strlen(livro[x].nome);
                    if(tamanho == 0)
                    {
                        printf("\t\t A entrada %d esta vazia! \n", x+1);
                        fflush(stdin);
                    }
                    else
                    {
                        printf("\n");
                        printf("\t Entrada %d", x+1);
                        printf("\t Livro: %s\n", livro[x].nome);
                        printf("\t Autor: %s\n", livro[x].autor);
                        printf("\t Editora: %s\n", livro[x].editora);
                        printf("\t Codigo: %d\n ", livro[x].codigo);
                        printf("\n\n"); 
                    }
                }
                system("pause");
                system("cls");
                break;
            default:
                printf("\n\n");
                printf("\t Opcao invalida \n");
                system("pause");
                system("cls");
        }

    }
}

Answer 1

Hello, from what I saw failed to initialize the array livro[], how are you testing whether the nome has been filled, you can make a loop at the beginning to clean up the trash in this field, example:

for (x=0; x<=4; x++)
    livro[x].nome[0] = 0;

or

for (x=0; x<=4; x++)
    memset(livro[x].nome, 0, sizeof(produto.nome));

Hug