Develop a ‘C’ program to create and implement a STACK using linked lists.

 

DATA STRUCTURE & ALGORITHM USING C – LAB (2018407)

 UNIT – 04

Develop a ‘C’ program to create and implement a STACK using linked lists.

Program:

# include <stdio.h>
# include <conio.h>
# include <stdlib.h>
struct stack
{
int data;
struct stack *next;
};
void push();
void pop();
void display();
typedef struct stack node;
node *start=NULL;
node *top = NULL;
node* getnode()
{
node *temp;
temp=(node *) malloc( sizeof(node)) ;
printf("\n Enter data ");
scanf("%d", &temp -> data);
temp -> next = NULL;
return temp;
}
void push(node *newnode)
{
node *temp;
if( newnode == NULL )
{
printf("\n Stack Overflow..");
return;
}
if(start == NULL)
{
start = newnode;
top = newnode;
}
else
{
temp = start;
while( temp -> next != NULL)
temp = temp -> next;
temp -> next = newnode;
top = newnode;
}
printf("\n\n\t Data pushed into stack");
}
void pop()
{
node *temp;
if(top == NULL)
{
printf("\n\n\t Stack underflow");
return;
}
temp = start;
if( start -> next == NULL)
{
printf("\n\n\t Popped element is %d ", top -> data);
start = NULL;
free(top);
top = NULL;
}
else
{
while(temp -> next != top)
{
temp = temp -> next;
}
temp -> next = NULL;
printf("\n\n\t Popped element is %d ", top -> data);
free(top);
top = temp;
}
}
void display()
{
node *temp;
if(top == NULL)
{
printf("\n\n\t\t Stack is empty ");
}
else
{
temp = start;
printf("\n\n\n\t\t Elements in the stack: \n");
printf("%5d ", temp -> data);
while(temp != top)
{
temp = temp -> next;
printf("%5d ", temp -> data);
}
}
}
char menu()
{
char ch;
clrscr();
printf("\n \t Stack operations using linked list.. ");
printf("\n -----------**********-------------\n");
printf("\n 1. Push ");
printf("\n 2. Pop ");
printf("\n 3. Display");
printf("\n 4. Quit ");
printf("\n Enter your choice: ");
ch = getche();
return ch;
}
void main()
{
char ch;
node *newnode;
do
{
ch = menu();
switch(ch)
{
case '1' :
newnode = getnode();
push(newnode);
break;
case '2' :
pop();
break;
case '3' :
display();
break;
case '4':
return;
}
getch();
} while( ch != '4' );
}
 
Output:
------------------------------------
    Stack operations using linked list
------------------------------------
1. Push
2. Pop
3. Display
4. Exit
Enter your choice: 1
Enter data to push into stack: 10
Data pushed to stack.
------------------------------------
  Stack operations using linked list
------------------------------------
1. Push
2. Pop
3. Display
4. Exit
Enter your choice: 2
 
Result: Thus, the program executed successfully.