Concatenate two sequential static lists

Question

I’m having trouble making a function that receives two lists and returns a third with the elements of the first concatenated with the elements of the second. I made the code but it returns me the third list with the elements of the first and with memory garbage instead of the elements of the second.

Lista concatenar(Lista lst1, Lista lst2) {

  Lista lst3 = (Lista) malloc(sizeof(Lista));
  int i,j;

  for (i = 0; i < lst1->fim; i++) {
    lst3->no[i] = lst1->no[i];
  }

  j = lst3->fim;

  for (i = 0; i < lst2->fim; i++) {
    lst3->no[j+1] = lst2->no[i];
  }

  return lst3;
}

Call the inserts(this function is working normal):

insere_elem(lst1, 4);
insere_elem(lst1, 12);
insere_elem(lst1, 0);

insere_elem(lst2, 11);
insere_elem(lst2, 18);
insere_elem(lst2, 25);

Struct lista:

struct lista {
  int no[max];
  int fim;
};

Answer 1

Since you were using pointers I needed to make some changes, where without such I do not see how the code would work... You have a "TL", controller, embedded in the struct, the "END"...use it. It’ll look something like this:

#include<stdio.h>
#include<stdlib.h>
#include<conio.h>
#define max 100

struct lista {
  int no[max];
  int fim;
};typedef struct lista Lista;

void init(Lista ** lst)
{
    *lst = (Lista*) malloc (sizeof(Lista));     
    (*lst) -> fim = 0;
}
Lista* concatenar(Lista * lst1, Lista * lst2) {
  Lista * lst;
  init(&lst);

  int i;

  for (i = 0; i < lst1->fim; i++) {
    lst->no[lst -> fim] = lst1->no[i];
    lst -> fim++;
  }

  for (i = 0; i < lst2->fim; i++) {
    lst->no[lst -> fim] = lst2->no[i];
    lst -> fim++;
  }

  return lst;
}


void insere_elem(Lista ** lst, int elem)
{
    if((*lst) -> fim <= max)
    {
        (*lst) -> no[(*lst) -> fim] = elem;
        (*lst) -> fim++;
    }   
}



void exibeLista(Lista * lst)
{
    for(int i=0; i < lst -> fim; i++)
        printf("%d ", lst -> no[i]);        
    printf("\n\n\n\n");

}

int main(void)
{
    Lista * lst1;
    init(&lst1);
    Lista * lst2;
    init(&lst2);

    Lista * lst3;


    insere_elem(&lst1, 4);
    insere_elem(&lst1, 12);
    insere_elem(&lst1, 0);

    insere_elem(&lst2, 11);
    insere_elem(&lst2, 18);
    insere_elem(&lst2, 25);

    exibeLista(lst1);
    exibeLista(lst2);

    lst3 = concatenar(lst1, lst2);
    exibeLista(lst3);
    getch();


}