Question

when I’m trying to push elements to a stack I get segmentation fault, but if I open address for stack(i marked them with “!!!”) and it’s symbols it accepts it. But this time in each push, it creates new address and doesn’t increase top value.

typedef struct
{
  struct table **symbols; // array of the stack
  int top; //index of the top element
  int size; //maximum size of the stack
}stack;

void push(stack *stck,struct table *element)
{  
    if(stck->top == stck->size)
    {
      printf("stack is full");
      return;
    }

    stck = malloc(sizeof(stack));                                          !!!
    stck->symbols = (struct table **)malloc(50 * sizeof(struct table*));   !!!

    printf("top : %d\n",stck->top);
    stck->top = stck->top++;
    printf("%d"&stck->top);
    stck->symbols[stck->top] = element;
    printf("top : %d\n",stck->top);
}

Answer 1

You have to construct your stack before you can push anything onto it. Eg. create function stack_new that will allocate memory for your stack and initialize its members:

stack * stack_new (size_t size)
{
    stack * stck = malloc(sizeof(stack));
    stck->top = -1;
    stck->size = size
    stck->symbols = (struct table **)malloc(size * sizeof(struct table*));
    return stck;
}

Now, once you properly constructed your stack with above function, you may pass it to push function.