SinglyLinkedList.c

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

struct node
{
	char usn[25],name[25],branch[25];
	int sem;
	long int phone;
	struct node *link;
};
typedef struct node * NODE;

NODE start = NULL;
int count=0;

NODE create()
{
	NODE snode;
	snode = (NODE)malloc(sizeof(struct node));

	if(snode == NULL)
	{
    	printf("\nMemory is not available");
    	exit(1);
	}
	printf("\nEnter the usn,Name,Branch, sem,PhoneNo of the student:");
	scanf("%s %s %s %d %ld",snode->usn, snode->name, snode->branch, &snode->sem, &snode->phone);
	snode->link=NULL;
	count++;
	return snode;
}

NODE insertfront()
{
	NODE temp;
	temp = create();
	if(start == NULL)
	{
       	return temp;
	}

	temp->link = start;
	return temp;
}

NODE deletefront()
{
	NODE temp;
	if(start == NULL)
	{
    	printf("\nLinked list is empty");
    	return NULL;
	}

	if(start->link == NULL)
	{
        	printf("\nThe Student node with usn:%s is deleted ",start->usn);
        	count--;
        	free(start);
        	return NULL;
	}
	temp = start;
	start = start->link;
	printf("\nThe Student node with usn:%s is deleted",temp->usn);
	count--;
	free(temp);
	return start;
}

NODE insertend()
{
	NODE cur,temp;
	temp = create();

	if(start == NULL)
	{
  	return temp;
	}
	cur = start;
	while(cur->link !=NULL)
	{
     	cur = cur->link;
	}
	cur->link = temp;
	return start;
}

NODE deleteend()
{
 	NODE cur,prev;
 	if(start == NULL)
 	{
    	printf("\nLinked List is empty");
    	return NULL;
 	}

 	if(start->link == NULL)
 	{
    	printf("\nThe student node with the usn:%s is deleted",start->usn);
    	free(start);
    	count--;
    	return NULL;
 	}

 	prev = NULL;
 	cur = start;
 	while(cur->link!=NULL)
 	{
     	prev = cur;
     	cur = cur->link;
 	}

  	printf("\nThe student node with the usn:%s is deleted",cur->usn);
  	free(cur);
  	prev->link = NULL;
  	count--;
  	return start;
}

void display()
{
	NODE cur;
	int num=1;

	if(start == NULL)
	{

    	printf("\nNo Contents to display in SLL \n");
    	return;
	}
	printf("\nThe contents of SLL: \n");
	cur = start;
	while(cur!=NULL)
	{
   	printf("\n||%d|| USN:%s| Name:%s| Branch:%s| Sem:%d| Ph:%ld|",num,cur->usn, cur->name,cur->branch, cur->sem,cur->phone);
   	cur = cur->link;
   	num++;
	}
	printf("\n No of student nodes is %d \n",count);
}

void stackdemo()
{
   int ch;
   while(1)
   {
 	printf("\n~~~Stack Demo using SLL~~~\n");
 	printf("\n1:Push operation \n2: Pop operation \n3: Display \n4:Exit \n");
 	printf("\nEnter your choice for stack demo");
 	scanf("%d",&ch);

 	switch(ch)
 	{
    	case 1: start = insertfront();
            	break;
    	case 2: start = deletefront();
            	break;
    	case 3: display();
           	break;
   	default : return;
 	}
   }
   return;
}

int main()
{
	int ch,i,n;
	while(1)
	{
    	printf("\n~~~Menu~~~");
    	printf("\nEnter your choice for SLL operation \n");
    	printf("\n1:Create SLL of Student Nodes");
    	printf("\n2:DisplayStatus");
    	printf("\n3:InsertAtEnd");
    	printf("\n4:DeleteAtEnd");
    	printf("\n5:Stack Demo using SLL(Insertion and Deletion at Front)");
    	printf("\n6:Exit \n");
    	printf("\nEnter your choice:");
    	scanf("%d",&ch);

    	switch(ch)
    	{
    	case 1 : printf("\nEnter the no of students:	");
             	scanf("%d",&n);
             	for(i=1;i<=n;i++)
                	start = insertfront();
             	break;

    	case 2: display();
            	break;

    	case 3: start = insertend();
            	break;

    	case 4: start = deleteend();
            	break;

    	case 5: stackdemo();
            	break;

    	case 6: exit(0);

    	default: printf("\nPlease enter the valid choice");

    	}
	}
}