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#include "position_stack.h"
#include <stdio.h>
#include <stdlib.h>
// Error handler for stack errors
void stack_error(int err)
{
switch (err)
{
case STACK_ERR_OVERFLOW:
printf("Error: Stack overflow\nBe kind and report this problem.");
break;
case STACK_ERR_UNDERFLOW:
printf("Error: Stack underflow\nBe kind and report this problem.");
break;
}
exit(1);
}
// Creates a new stack
struct PositionStack *create_pos_stack(int capacity)
{
struct PositionStack *stack_pt = malloc(sizeof(struct PositionStack));
stack_pt->capacity = capacity;
stack_pt->top = -1;
stack_pt->items = malloc(sizeof(struct Position) * capacity);
return stack_pt;
}
// Adds a new item to a stack
void pos_stack_push(struct PositionStack *stack_pt, struct Position pos)
{
// Avoid a overflow by checking if the stack is full
if (stack_pt->top == stack_pt->capacity - 1)
{
stack_error(STACK_ERR_OVERFLOW);
}
// Add an element and increase the top index
stack_pt->items[++stack_pt->top] = pos;
}
// Returns the topmost item of a stack
struct Position pos_stack_peek(struct PositionStack *stack_pt)
{
// Avoid a underflow by checking if the stack is empty
if (stack_pt->top == -1)
{
stack_error(STACK_ERR_UNDERFLOW);
}
return stack_pt->items[stack_pt->top];
}
// Deletes the topmost item of a stack
struct Position pos_stack_pop(struct PositionStack *stack_pt)
{
// Avoid a underflow by checking if the stack is empty
if (stack_pt->top == -1)
{
stack_error(STACK_ERR_UNDERFLOW);
}
// Decrease the stack size by 1 and return the popped element
return stack_pt->items[stack_pt->top--];
}
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