Stack it up!

Computer Science Level 1

Which line of this implementation of a queue should be changed in order to obtain a stack?

C++

#include <stdlib.h>

struct thing {
int size; /* size of contents */
int bottom; /* first used location */
int top; /* first unused location */
int *elements; /* array of elements */
};

struct thing *thingCreate(int size)
{
struct thing *t;

t = malloc(sizeof(*t));

t->size = size;
t->bottom = t->top = 0;
t->elements = malloc(sizeof(int) * size);

return t;
}

void Push(struct thing *t, int value)
{
t->elements[t->top++] = value;
}

int Pop(struct thing *t)
{
return t->elements[t->bottom++];
 }