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@RenatoUtsch

RenatoUtsch/stack.c

Created November 28, 2012 17:42
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  1. RenatoUtsch created this gist Nov 28, 2012.
    85 changes: 85 additions & 0 deletions stack.c
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    Original file line number Diff line number Diff line change
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    #include <stdlib.h>
    #include <string.h>
    #include "stack.h"

    typedef struct StackNode {
    StackItem item; /** The data of this node. **/
    struct StackNode *next; /** The next node (the one below the top). **/
    } StackNode;

    struct Stack {
    size_t count; /** The number of items in the stack. **/
    StackNode *top; /** The top item of the stack. **/
    };

    Stack *stackCreate()
    {
    /* Create a stack and set everything to the default values. */
    Stack *stack = (Stack *) malloc(sizeof *stack);
    if(stack == NULL)
    return NULL;

    stack->count = 0;
    stack->top = NULL;

    return stack;
    }

    void stackDestroy(Stack *stack)
    {
    stackClean(stack);
    free(stack);
    }

    void stackClean(Stack *stack)
    {
    while(!stackIsEmpty(stack))
    stackPop(stack);
    }

    bool stackIsEmpty(Stack *stack)
    {
    return stack->top == NULL ? true : false;
    }

    size_t stackSize(Stack *stack)
    {
    return stack->count;
    }

    StackItem stackTop(Stack *stack)
    {
    return stack->top->item;
    }

    bool stackPush(Stack *stack, StackItem item)
    {
    StackNode *newNode = (StackNode *) malloc(sizeof *newNode);
    if(newNode == NULL)
    return false;

    newNode->item = item;
    newNode->next = stack->top;
    stack->top = newNode;

    stack->count += 1;
    return true;
    }

    StackItem stackPop(Stack *stack)
    {
    StackNode *oldTop;
    StackItem item;

    if(stack->top == NULL)
    return 0; /** @todo Make a better way to return this error. **/

    oldTop = stack->top;
    item = oldTop->item;
    stack->top = oldTop->next;
    free(oldTop);
    oldTop = NULL;

    stack->count -= 1;
    return item;
    }
    26 changes: 26 additions & 0 deletions stack.h
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    #ifndef STACK_H_INCLUDED
    #define STACK_H_INCLUDED

    #include <stdlib.h>

    #if !defined(__bool_true_false_are_defined) && !defined(__cplusplus)
    typedef int bool;
    #define true 1
    #define false 0
    #define __bool_true_false_are_defined
    #endif

    #define StackItem char

    typedef struct Stack Stack;

    Stack *stackCreate();
    void stackDestroy(Stack *stack);
    void stackClean(Stack *stack);
    bool stackIsEmpty(Stack *stack);
    size_t stackSize(Stack *stack);
    StackItem stackTop(Stack *stack);
    bool stackPush(Stack *stack, StackItem item);
    StackItem stackPop(Stack *stack);

    #endif