How to fix Deque implementation - c

Question

I'm trying to do a implementation of a deque with dynamic allocation, but I'm having some trouble since the values of the variables in the struct are different out of the function initialize, and I dont know why.
By some reason, the program always end up with a segmentation fault in the push_front/back part.
// C program for vetor implementation of d
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef int data;
// A structure to represent a d
typedef struct deque
{
int front, rear, size;
unsigned int capacidade;
data* vetor;
}deque;
// function to create a d of given capacidade.
// It initializes size of d as 0
void initialize(deque *d, unsigned int capacidade){
d = (deque*) malloc(sizeof(deque));
d->capacidade = capacidade;
d->front = 0;
d->size = 0;
d->rear = capacidade-1; // This is important, see the enqueue
d->vetor = (data*) malloc(d->capacidade * sizeof(data));
}
// deque is full when size becomes equal to the capacidade
int full(deque* d){
if(d->size == d->capacidade)
return 1;
else return 0;
}
// deque is empty when size is 0
int empty(deque* d){
return (d->size == 0);
}
// Function to add an item to the d.
// It changes rear and size
int push_back(deque* d, int item){
if (full(&d))
return 0;
d->rear = (d->rear + 1)%d->capacidade;
d->vetor[d->rear] = item;
d->size = d->size + 1;
}
int push_front(deque* d, int item){
if (full(&d))
return 0;
d->front = (d->front - 1+d->capacidade)%d->capacidade;
d->vetor[d->front] = item;
d->size = d->size + 1;
}
// Function to remove an item from d.
// It changes front and size
int pop_front(deque* d){
if (empty(&d))
return 0;
int item = d->vetor[d->front];
d->front = (d->front + 1)%d->capacidade;
d->size = d->size - 1;
return item;
}
int pop_back(deque* d){
if (empty(&d))
return 0;
int item = d->vetor[d->rear];
d->rear = (d->rear - 1+d->capacidade)%d->capacidade;
d->size = d->size - 1;
return item;
}
// Function to get front of d
int front(deque* d)
{
if (empty(d))
return 0;
return d->vetor[d->front];
}
// Function to get rear of d
int rear(deque* d)
{
if (empty(d))
return 0;
return d->vetor[d->rear];
}
// Driver program to test above functions./
int main()
{
deque* d;
int operacoes=0, tamdeque=0, i=0;
char opcao[100];
scanf("%d %d", &operacoes, &tamdeque);
initialize(&d, tamdeque);
while(i<=operacoes){
scanf("%s", opcao);
if(!strcmp(opcao, "insereI")){
if(full(&d)){
printf("cheia\n");
}
else{
data item;
scanf("%d", &item);
printf("%u\n", &d->capacidade);
push_front(&d, item);
}
}
else if(!strcmp(opcao,"insereF")){
if(full(&d)){
printf("cheia\n");
}
else{
data item;
scanf("%d", &item);
push_back(&d, item);
}
}
else if(!strcmp(opcao, "removeI")){
if(empty(&d)){
printf("vazia\n");
}
else{
pop_front(&d);
}
}
else if(!strcmp(opcao, "removeF")){
if (empty(&d)){
printf("vazia\n");
}
else{
pop_back(&d);
}
}
i++;
}
return 0;
}

Answer 1

Mis-match arguments
In many places, the following type of error. Readily findable will all warnings enabled.
warning: passing argument 1 of 'pop_back' from incompatible pointer type [-Wincompatible-pointer-types]
int push_back(deque* d, int item){
// if (full(&d))
if (full(d))
main()
// deque* d;
deque d;
initialize(&d, tamdeque);
mixing int/unsigned math.
Recommend a design change to use just one.
Missing return value
Minor: int push_back(), push_front()
Other problems exist. (About 30 total warnings)