A simple demonstration of stacks in ANSI C

stack.c

/*
 * stacks.c
 *
 * An example (and probably not great) stack implimentation in ANSI C
 * Licensed under "Do what you want" by Leo Adamek (leo.adamek.me), 2012
 *
 * Notes:
 * This program is a demonstration of stacks in C.
 * The main function of this program is just a demonstration of the stack
 */

#include <stdio.h>
#include <stdlib.h>


/* Type Definition for Stack */

typedef struct{
	int top;
	int max_height;
	float data[];
}Stack;

/* Prototype Declarations */

void push(Stack* st, float value);
float pop(Stack* st);
void init(Stack* st, int max);
int full(Stack* st);
int get_top(Stack* st);
int get_height(Stack* st);
void st_print(Stack* st);

int main(int argc, char* argv[]){
	Stack s;
	int i;
	init(&s, 0x65536); /* Stack of maximum height 0x65536 */
	
	st_print(&s);
	
	push(&s, 3.14159);
	push(&s, 0.6325);
	push(&s, 0xD1C3);
	push(&s, 0150);
	
	st_print(&s);
	
	printf("Top of stack is: %g\n",pop(&s));
	
	push(&s, 0x63);
	
	st_print(&s);
	
	// This is an interesting one...
	push(&s, pop(&s) + pop(&s));
	
	st_print(&s);
	
	printf("Stack Top Is: %d\n", get_top(&s) );
	printf("Stack Maximum Height Is: %d\n", get_height(&s) );
	
	printf("Emptying the stack...\n");
	
	for(i=0;i<get_top(&s);i++){
		pop(&s);
	}
	
	printf("Filling the stack (a bit)...\n");
	
	for(i=0;i<50;i++){
		push(&s, (float)0xDEADBEEF);
		if(i%5 == 0){
			printf("Pushed item %d\n",i);
		}
	}
	
	printf("Stack Filled... (%g Items)\n",get_top(&s));
	
	printf("Press Any Key...");
	getch();
	return 0;
}

/* Get current stack height and maximum height */
int get_top(Stack* st){return st->top;}
int get_height(Stack* st){return st->max_height;}


/* Add a value to the stack */
void push(Stack* st, float value){
	st->data[st->top] = value;
	(st->top)++;
}

/* Retreieve a value from the stack */
float pop(Stack* st){
	(st->top)--;
	return (st->data[st->top]);
}

/* Initialise a stack */
void init(Stack* st, int max){
	st->top = 0;
	st->max_height = max;
}

/* check if a stack is full */
int full(Stack* st){
	return (st->top >= st->max_height);
}

/* print out a stack */
void st_print(Stack* st){
	int i;
	if(st->top == 0){
		printf("Stack Is Empty.\n");
	}else{
		printf("Stack Contents:\n");
		for(i=0;i<st->top;i++){
			printf("%g\t",st->data[i]);
		}
		printf("\n\n");
	}
}