C Program to show Linked list implementation of stack

 

# include< stdio.h>
# include< stdlib.h>
struct link
{
int info;
struct link *next;
};
void display(struct link *rec)
{
while(rec != NULL)
{
printf(" %d ",rec->info);
rec = rec->next;
}
}
struct link * push(struct link *rec)
{
struct link *new1;
printf("\n Enter value for stack:-");
new1 = (struct link *)malloc(sizeof(struct link));
scanf("%d", &new1->info);
new1->next = rec;
/* next pointer of new1 is holding the address of the first node of the list. so new1 is the first node now.*/
rec = new1;
/* from this point the pointer rec is pointing the first node of the list. */
return rec;
}
struct link * pop(struct link *rec)
{
struct link *temp;
if(rec == NULL)
{
printf("\n Stack is empty");
}
else
{
/*rec is pointing the first node of the list.*/
temp = rec->next;
/*temp is pointing the second node of the list. */
free(rec);
rec = temp;
printf("\n After pop operation the stack is as follows:\n");
display(rec);
if(rec == NULL)
printf("\n Stack is empty");
}
return rec;
}
int selection()
{
int choice;
do
{
printf("\n 1<-Push ");
printf("\n 2<-Pop");
printf("\n 3<-Quit");
printf("\n Input your choice :");
scanf("%d", &choice);
if(choice <1 || choice >3)
printf("\n Incorrect choice-> Try once again");
} while(choice <1 || choice >3);
return choice;
}
void main()
{
struct link *start ;
int choice;
clrscr();
start = NULL;
do
{
choice = selection();
switch(choice)
{
case 1:
start = push(start);
printf("\n After push operation stack is as follows:\n");
display(start);
break;
case 2:
start = pop(start);
break;
default :
printf("\n End of session");
}
} while(choice != 3);
getch();
}