20-queue-and-stack/stack.h
2025-04-09 08:31:55 +02:00

96 lines
2.9 KiB
C

/*----------------------------------------------------------
* HTBLA-Leonding / Class: <your class>
* ---------------------------------------------------------
* Exercise Number: S03
* Title: Stack Inteface
* Author: Marc Tismonar
* ----------------------------------------------------------
* Description:
* The declaration of a stack abstract data type.
* ----------------------------------------------------------
*/
/** The type of the integer stack: IntStack */
typedef struct IntStackData* IntStack;
/**
* Obtains ('creates') and provides a 'new' stack instance.
* Any stack obtained via this function MUST be released using
* function `release_stack()`.
*
* Note: This function does not make any assumptions
* about how stack components, esp. nodes, are allocated.
*
* @return IntStack The stack instance or 0, if no stack could by instantiated.
*/
IntStack stack_obtain();
/**
* Releases a stack that was obtained earlier via function `obtain_stack`.
* Released stacks MUST NOT be used anymore.
*
* Note: The implementation of this function does not make any assumptions
* about the allocation method of stack elements, but MUST match the implementation
* of function `obtain_stack` as its inverse function.
*
* @param p_stack The pointer to the stack to release. The value of the pointer
* is set to 0, if the stack was successfully released, otherwise it is left untouched.
*/
IntStack stack_release(IntStack* p_stack);
/**
* Determines whether or not the given stack is valid.
*
* @param stack The stack to evaluate.
* @return `True` if the stack is valid, false otherwise.
*/
bool stack_is_valid(IntStack stack);
/**
* Determines whether or not the stack contains at least one item.
*
* @param stack The stack to evaluate.
* @return `False` if the stack contains one or more items, `true` otherwise.
*/
bool stack_is_empty(IntStack stack);
/**
* Provides the number of values stored in the stack.
*
* @param stack The stack to evaluate.
* @return The number of values the stack contains.
*/
int stack_get_size(IntStack stack);
/**
* Clears the given stack by removing all values from the stack.
*
* @param stack The stack to clear.
*/
void stack_clear(IntStack stack);
/**
* Inserts the given value to the stack.
*
* @param stack The stack to which the value shall be appended.
* @param value The value to append to the stack.
*/
void stack_push(IntStack stack, int value);
/**
* Provides the value that 'pop' would provided but WITHOUT removing
* this value from the stack.
*
* @param stack The stack from which the value shall be peeked.
* @return The next value or 0, if the stack is empty.
*/
int stack_peek(IntStack stack);
/**
* Provides AND removes the top-most value from the stack.
*
* @param stack The stack from which the value be removed shall be returned.
* @return The value or 0, if the stack is empty.
*/
int stack_pop(IntStack stack);