stack.c

/*
 Own code implementated by Rajendra Kadam

 Source code is available for download on my website

 link: iamrajendra.pythonanywhere.com 

 */

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


// implementations of stack using linked list
struct stackNode
{
	/* data */
	int data;
	struct stackNode* next;
};

struct stackNode* top = NULL;


// stack functions prototypes
void push();
void pop();
void display();

void main(){

	int choice;
	clrscr();

	while(1){

		// operations to be performed
		printf("1: Push\n");
		printf("2: Pop\n");
		printf("3: Display\n");
		printf("4: Exit\n");

		printf("Enter Command: \n");
		scanf("%d",&choice);

		// making program menu driven
		switch(choice){

			case 1: push();
					break;
			case 2: pop();
					break;
			case 3: display();
					break;
			case 4: exit(0);
					break;
		}
	}
	getch();
}

// functions implementation
// pushing the node into stack
void push(){

		// make a new node to store data
		int data;
		struct stackNode* newNode;
		newNode = (struct stackNode*)malloc(sizeof(struct stackNode));

		// take the data to be stored
		printf("Enter data: \n");
		scanf("%d",&data);

		newNode->data = data;
		newNode->next = NULL;

		// checking is top null?
		if (top == NULL){
			// make the top point the first node
			top = newNode;
		}
		else{
			// update the top if it is not first node
			newNode->next = top;
			top = newNode;
		}

		// display the stack
		display();
}

// pop node from stack

void pop(){

	// sanity check for is stack empty?
	if (top == NULL){

		printf("Stack Empty\n");
	}
	else{
		top = top->next;
		printf("Data popped.\n");

		display();
	}

}
void display(){

	struct stackNode* temp;
	temp = top;

	printf("_____________\n");
	printf("Stack is now\n");
	while(temp != NULL){

		printf("%d ",temp->data);
		temp = temp->next;
	}
	printf("\n");
	printf("_____________");
	printf("\n");
}