Linked stack in C

stack.c

#include "..\Header\stack.h"
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <assert.h>

void stackpush(Stack * stack, int value)
{
		assert(stack != NULL);
		if(stack->top == NULL)
		{
			stack->top = malloc(sizeof(Node));
			stack->top->value = value;
			stack->isempty = false;
		}
		else
		{
			Node * old = stack->top;
			stack->top = malloc(sizeof(Node));
			stack->top->next = old;
			stack->top->value = value;
		}
}

int stackpop(Stack * stack)
{
		assert(stack != NULL);
		int value = stack->top->value;
		Node * oldtop = stack->top;
		stack->top = stack->top->next;
		free(oldtop);
		if(stack->top == NULL)
			stack->isempty = true;
		return value;
}

void stackdispose(Stack * stack)
{
		assert(stack != NULL);
        while(! stack->isempty)
        	stackpop(stack);
}

stack.h

typedef struct node_t
{
		int value;
		struct node_t * next;
} Node;

typedef struct stack_t
{
		Node * top;
		int isempty;

} Stack;

void stackpush(Stack*, int);
int stackpop(Stack*);
void stackdispose(Stack*);