Q.28 Implement Stack using Linked List. (AKTU. 2009-10)
Related Questions -
Q. Give an algorithm for push and pop operations on stack. Also write a program in C language to create a stack of even numbers. (AKTU. 2012-13)
Ans.
#include<stdio.h>
#include<conio.h>
#include<malloc.h>
/*structure of single stack node*/
struct node{
int info;
struct node *next;
};
struct node *top_of_stack, *temp, *new_node;
/* To allocate memory for a node*/
struct node* create_node(void);
/* loop control*/
int flag = 0;
/*Elementry stack functions are :*/
/* 1)Insertion at the TOP OF STACK (PUSH) */
void push(void);
/* 2)Deletion at TOP OF STACK (POP)*/
void pop(void);
/* 3)Traverse the stack*/
void traverse(void);
/* 4)Main - Menu to access all the above functions*/
void main_menu(void);
void main()
{
clrscr();
top_of_stack = NULL;
printf("\n\t\tIMPLEMENTATION OF STACK BY LINKED LIST ");
printf("\n\t\tCreated by ABHINAV SHALABH KULSHRESTHA");
printf("\n\n");
while(1)
{
main_menu();
if(flag == 1)
break;
}
}
void main_menu(void)
{
int ch;
char c;
printf("\nMAIN-MENU");
printf("\nPress 0. To PUSH.\n");
printf("\nPress 1. To POP.\n");
printf("\nPress 2. To TRAVERSE.\n");
printf("\nPress any other key to exit.\n");
printf("\nEnter your choice.\n");
c = NULL;
c = getche();
ch = c - '0';
switch(ch)
{
case 0: push();
traverse();
break;
case 1: pop();
traverse();
break;
case 2: traverse();
break;
default: flag = 1;
break;
}/* end switch case*/
}/* end main_menu */
void push(void)
{
int num;
printf("\nInsert at top of stack (PUSH)");
printf("\nEnter the number.\n ");
scanf("%d", &num);
new_node = create_node();
new_node -> info = num;
new_node -> next = NULL;
if(top_of_stack == NULL)
top_of_stack = new_node;
else
{
new_node -> next = top_of_stack;
top_of_stack = new_node;
}
}
void pop(void)
{
printf("\nDelete at top of stack (POP)");
temp = top_of_stack;
top_of_stack = temp -> next;
free(temp);
}
void traverse(void)
{
printf("\nCurrent status of stack : \n");
temp = top_of_stack;
printf("\nTop Of Stack*-->");
if(top_of_stack != NULL)
{
while(temp -> next != NULL)
{
printf("%d-->",temp ->info);
temp = temp ->next;
}
printf("%d",temp ->info);
printf("||*\n");
}
else
{
printf("stack is Empty");
printf("||*\n");
}
}
struct node* create_node(void)
{
struct node *tmp = NULL;
tmp =(struct node*)( malloc(sizeof(struct node)));
if(tmp != NULL)
return tmp;
else
{
printf("\nMemory is not Free.Press any key to continue");
getch();
return NULL;
}
}
