#include "stack.h"

void stack_push(double* stack, int* top, int size, double item)
{
	// TODO: Check whether the stack is full before adding new item
	// TODO: Check if all inputs are valid
	//       (e.g. 'stack' and 'top' must not be a null pointer;
	//             'size' is positive integer; 'top' < 'size')
	if(stack == 0 || top == 0 || size <= 0)
	{
		printf("ERROR: Invalid arguments.\n");
		return;
	}
	if(*top >= size)
	{
		printf("ERROR: The stack is full.\n");
		return;
	}
	
	*(stack + (*top)++) = item;
}

double stack_pop(double* stack, int* top)
{
	// TODO: Check if all inputs are valid
	//       (e.g. 'stack' and 'top' must not be a null pointer;
	//             'top' must be greater than 0)
	if(stack == 0 || top == 0 || *top <= 0)
	{
		printf("ERROR: Invalid arguments.\n");
		return;
	}

	return *(stack + --(*top));
}

void stack_clear(double* stack, int* top, int size)
{
	int i;
	// TODO: Check if all inputs are valid
	//		(e.g. 'stack' and 'top' must not be a null pointer)
	if(stack == 0 || top == 0 || size <= 0)
	{
		printf("ERROR: Invalid arguments.\n");
		return;
	}

	// TODO: Reset all elements in 'stack' to zero.
	for(i = 0; i < size; i++)
		*(stack + i) = 0.0;
	
	*top = 0;
}

void stack_print(double* stack, int* top)
{
	int i;
	if(stack == 0 || top == 0)
	{
		printf("ERROR: Invalid arguments.\n");
		return;
	}
	
	for(i = 0; i < *top; i++)
		printf("%d: %8.2f\n", i, *(stack + i));
	printf("\n");
}