stack0.h

#include <stdlib.h>
#define RogueValue -9999

typedef struct node {
	int num;
	struct node *next;
} Node, *NodePtr;

typedef struct stackType {
	NodePtr top;
} StackType, *Stack;

Stack initStack() {
	Stack sp = (Stack) malloc(sizeof(StackType));
	sp -> top = NULL;
	return sp;
}

int empty(Stack S) {
	return (S -> top == NULL);
} //end empty

void push(Stack S, int n) {
	NodePtr np = (NodePtr) malloc(sizeof(Node));
	np -> num = n;
	np -> next = S -> top;
	S -> top = np;
} //end push

int pop(Stack S) {
	if (empty(S)) return RogueValue;
	int hold = S -> top -> num;
	NodePtr temp = S -> top;
	S -> top = S -> top -> next;
	free(temp);
	return hold;
} //end pop