How to allocate a dynamic stack with user-provided size?

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I want to allocate a dynamic stack with the size provided by the user, then treat it as a "vector" would be more or less what I did in the function ALOCA?

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <stdbool.h>
struct figuras
{
    char nome[100];
    char idade[5];
    char selecao[100];
};
typedef struct elemento* Pilha;

struct elemento
{
    struct figuras dados;
    struct elemento *prox;
};
typedef struct elemento Elem;
//FUNCOES
Pilha* cria_Pilha();


void menu()
{
    printf("1 - Criar Pilha Dinamicamente\n2 - Inserir Elementos\n3 - Remover Elementos\n4 - Imprimir Elementos\n5 - Checar Pilha vazia\n6 - Checar Pilha Cheia\n7 - Destruir Pilha\n");
    printf("Digite uma opcao\n");
}

int main()
{
    int *ptam;
    int tampilha, op;
    do{
    menu();
    scanf("%d", &op);
    if(op == 1)//CRIAR
    {
        system("cls");
        printf("Digite o Tamanho da sua Pilha\n");
        scanf("%d", &tampilha);
        //ptam = &tampilha;
        Pilha *pi = cria_Pilha();
        ALOCA(pi, tampilha);
    }else
        if(op == 2)//PUSh (INSERIR)
        {

        }else
            if(op == 3)//POP(remover1)
            {

            }else
                if(op == 4)//IMRPIMIR
                {

                }else
                    if(op == 5)//Checar pilha vazia
                    {

                    }else
                        if(op == 6)//CHECAR PILHA CHEIA
                        {

                        }else{//DESTRUIR PILHA
                        }



 }while(op != 8);

    return 0;
}



//funcoes escopo
Pilha* cria_Pilha()
{
    Pilha* pi = (Pilha*) malloc(sizeof(Pilha));
    if(pi != NULL){
        *pi = NULL;
    }

    return pi;
}
int ALOCA(Pilha* pi, int tam)
{
    if(pi == NULL)
        return 0;
    Elem* no;
    no = (Elem*) malloc(tam * sizeof(Elem));
    if(no == NULL)
        return 0;
}
c memory-management stack malloc

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1 answer

2

It’s not like that. If it’s a pile then it would be something like this:

Pilha pi = malloc(sizeof(Elem) * tam);

You don’t need anything else but to decide what to do if there is an allocation error (which is wrong in the function presented in the question. You allocate space for the whole stack, that is, you have space for each of the elements that you can put in it.

If you want a list turned on, and part of the code indicates this, all you have to do is:

Elem *no = malloc(sizeof(Elem));

I put in the Github for future reference.

You’d also need to fix the mistake, which is wrong in the question.

In this case there will not be a structure that will support the list, each node in the list is part of it.

The code mixes concepts, need to decide if you want a stack or list on.

The code has several other errors, and it can be written much better.

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