A project for C/C++, Data Structures, and System Programming by Karl Krauss for fall 2011.

Approximately 3 hours including taking the time to full grasp all concepts that were used, this was much simpler than doubly linked list as the “hard” parts had been figured out already.

The purpose of this project was to create a library for stacks.

In order to successfully accomplish/perform this project, the listed resources/experiences need to be consulted/achieved:

• understand functions
• understand pointers
• understand structs
• understand malloc()

This was the next evolution of the doubly linked list library. This is the stack library, taking what I learned from implementing the dl library this was much simpler.

• variables
• pointers
• selection
• i/o
• repetition
• functions
• structures
• libraries

• Pointers
• Malloc/new
• linked list
• Doubly linked list
• Libraries

• Terminal I/O

This is the header file:

#ifndef			STACK_H
 
#define      	STACK_H
 
 
 
 
 
struct node { //predefined structure with one variable (
 
	int value;
 
	struct node *next;
 
	struct node *prev;
 
};
 
typedef struct node Node;
 
 
 
struct stack {// predefined structure for use of returns in functions allow for easy access to stack.  *end is top of stack
 
	Node *start;
 
	Node *end;
 
};
 
typedef struct stack Stack;
 
 
 
Stack *push(Stack *myStack, int input);
 
Node *pop(Stack *myStack);
 
Node *peek(Stack *myStack);
 
 
 
 
 
 
 
//minimum variables needed in main: int input, Node *tmp, Node *tmp2, List *myList.
 
 
 
#endif

This is the code:

typedef struct list List;
 
	in List: * start will be the stack and *end the top of the stack.
 
*/
List *push(List *myList, Node *tmp, int input);
List *pop(List *myList, Node *tmp, int i);
void peek(List *myList);
int main()
{
 
	List *myList;
	//Node *stack, *top
	Node *tmp;
	int i=0, input;
 
	//tmp = stack = top = NULL;
	myList=(List *)malloc(sizeof(List));
	myList->start =myList->end = tmp = NULL;
 
	printf("Please enter a value (-1 to stop): ");//puts kept printing a new line
 
	scanf("%d", &input);
 
	while (input != -1)
	{
		push(myList, tmp, input);
		i++;
		printf("Please enter a value (-1 to stop): ");
		scanf("%d", &input);
 
	}
 
	peek(myList);
	getchar();
	getchar();
	while (i != 0)//tmp = (Node *)pop(myList, tmp, i)) != NULL) 
	{
 
		myList=pop(myList, tmp, i);
		i--;
	}
 
	return 0;
}
 
List *push(List *myList, Node *tmp, int input)// pushing a new value onto the top of the stack
{
	myList = newNode(myList, tmp, input);
 
	return myList;
}
 
List *pop(List *myList, Node *tmp, int i)// popping value off the top of the stack
{
 
	int x;
	tmp = myList->start;
 
	for(x=1; x<i; x++)
	{
		tmp = tmp->next;
	}
 
	printf("value: %d\n", tmp -> value);
	deleteNode(myList, tmp, i);
 
	return myList;
}
 
void peek(List *myList)// checking to see whats on the top of the stack
{
	if(myList->start == NULL)
	{
		printf("The stack is empty\n");
	}
	else
	{
		printf("THe value at the top of the stack is: %d\n", myList->end->value);
	}
}

• As with doubly linked lists, I really learned a lot. This library was written quite some time ago and the best part is when I came back to it, I had learned enough to realize I could vastly improve upon it. Something I will possibly do in the future.