Linked list

01. singlylinkedlist.cpp

@@ -0,0 +1,298 @@
+
+//// happy coding ////
+//// chant hare krishna /////
+//// rk dagar ///////
+
+#include<bits/stdc++.h>
+using namespace std;
+
+class node{
+	public:
+		int data;
+		node *next;
+};
+
+node *start = NULL;
+node *createll(node *);
+node *display(node *);
+node *insertbeg(node *);
+node *insertend(node *);
+node *insertbefore(node *);
+node *insertafter(node *);
+node *deletebeg(node *);
+node *deleteend(node *);
+node *deletenode(node *);
+node *deleteafter(node *);
+node *deletelist(node *);
+node *sortll(node *);
+int main()
+{
+	int option;
+	do{
+		cout<<"\n\n *******MAIN MENU*******";
+		cout<<"\n 1:  Create a list ";
+		cout<<"\n 2:  Display the list ";
+		cout<<"\n 3:  Add a node at the begining";
+		cout<<"\n 4:  Add a node at the end";
+		cout<<"\n 5:  Add a node before a given node";
+		cout<<"\n 6:  Add a node after a given node";
+		cout<<"\n 7:  delete a node from the begining";
+		cout<<"\n 8:  delete a node from the end";
+		cout<<"\n 9:  delete a given node";
+		cout<<"\n 10: delete a node after given node";
+		cout<<"\n 11: delete entire list";
+		cout<<"\n 12: sort the list";
+		cout<<"\n 13: exit\n";
+		cin>>option;
+		switch(option)
+		{
+			case 1:
+				start= createll(start);
+				cout<<"\n linked list created";
+				break;
+			case 2:
+				start= display(start);
+				break;
+		    case 3:
+		    	start= insertbeg(start);
+		    	break;
+		    case 4:
+		    	start= insertend(start);
+		    	break;
+		    case 5:
+		    	start= insertbefore(start);
+		    	break;
+		    case 6:
+		    	start= insertafter(start);
+		    	break;
+		    case 7:
+		    	start= deletebeg(start);
+		    	break;
+		    case 8:
+		    	start= deleteend(start);
+		    	break;
+		    case 9:
+		    	start= deletenode(start);
+		    	break;
+		    case 10:
+		    	start= deleteafter(start);
+		    	break;
+		    case 11:
+		    	start= deletelist(start);
+		    	cout<<"\n linked list deleted";
+		    	break;
+		    case 12:
+		    	start= sortll(start);
+		    	break;
+
+		}
+	}while(option!=13);
+
+	return 0;
+}
+
+node* createll(node *start)
+{
+	node* nn,*p;
+	int num;
+	cout<<"\nenter -1 to end\n";
+	cin>>num;
+	while(num!=-1)
+	{
+		nn=new node();
+		nn->data=num;
+		nn->next=NULL;
+		if(start==NULL)
+		{		
+		    start=nn;
+		}
+		else
+		{
+			p=start;
+			while(p->next!=NULL)
+				p=p->next;
+			p->next=nn;
+		}
+		cin>>num;
+	}
+	return start;
+}
+node *display(node* start)
+{
+	node *t=start;
+	while(t!=NULL)
+	{
+		cout<<t->data<<" -> ";
+		t=t->next;
+	}
+	cout<<"NULL\n";
+	return start;
+}
+
+node *insertbeg(node *start)
+{
+	node *nn= new node();
+	int num;
+	cin>>num;
+	nn->data=num;
+	nn->next=start;
+	start=nn;
+
+	return start;
+}
+
+node *insertend(node *start)
+{
+	node *nn=new node();
+	node *p=start;
+	int num;
+	cin>>num;
+	nn->data=num;
+	nn->next=NULL;
+	while(p->next!=NULL)
+	{
+		p=p->next;
+	}
+	p->next=nn;
+
+
+	return start;
+
+
+}
+node *insertbefore(node *start)
+{
+	node *nn= new node();
+	node *p=start;
+	node *preptr;
+	int num,val;
+	cin>>num>>val;
+	nn->data=num;
+	while(p->data!=val)
+	{
+		preptr=p;
+		p=p->next;
+	}
+	preptr->next=nn;
+	nn->next=p;
+
+	return start;
+
+}
+
+node *insertafter(node *start)
+{
+	node *nn=new node();
+	node *p= start,*pre=start;
+	int num,val;
+	cin>>num>>val;
+	nn->data=num;
+	while(pre->data!=val)
+	{
+		pre= p;
+		p=p->next;
+	}
+nn->next=p;
+pre->next=nn;
+
+return start;
+}
+
+node *deletebeg(node *start)
+{
+	node *nn;
+	nn= start;
+	start=nn->next;
+	free(nn);
+
+	return start;
+}
+
+node *deleteend(node *start)
+{
+	node *nn=start,*p;
+	while(nn->next!=NULL)
+	{
+		p=nn;
+		nn=nn->next;
+	}
+	p->next=NULL;
+	free(nn);
+
+	return start;
+}
+
+node *deletenode(node *start)
+{
+	int val;
+	cin>>val;
+	node *p=start,*pre;
+	while(p->data==val) 
+	{
+		start= deletebeg(start);
+	return start;
+}
+while(p->data!=val)
+{
+	pre=p;
+	p=p->next;
+}
+pre->next=p->next;
+free(p);
+
+return start;
+
+}
+
+node *deleteafter(node *start)
+{
+	node *nn,*p=start;
+	nn=start;
+	int num;
+	cin>>num;
+	while(p->data!=num)
+	{
+		p=nn;
+		nn=nn->next;
+	}
+	p->next=nn->next;
+	free(nn);
+
+	return start;
+}
+
+node *deletelist(node *start)
+{
+	node *n=start;
+	while(n!=NULL)
+	{
+		start= deletebeg(start);
+		n=start;
+	}
+
+	return start;
+}
+
+node *sortll(node *start)
+{
+	node *p1,*p2;
+	int t;
+	p1=start;
+	while(p1->next!=NULL)
+	{
+		p2=p1->next;
+		while(p2!=NULL)
+		{
+			if(p1->data>p2->data)
+			{
+				t=p1->data;
+				p1->data=p2->data;
+				p2->data=t;
+			}
+			p2=p2->next;
+		}
+		p1=p1->next;
+	}
+	return start;
+}
+