two way linked list

#include #include struct node { int data; struct node *next; struct node *prev; }*start,*last,*newnode,*p,*ptr; void main() { int ch; clrscr(); do { printf("**********MAIN MENU***********"); printf("\n1.add start"); printf("\n2.add middle"); printf("\n3.addlast"); printf("\n4.delete"); printf("\n5.show"); printf("\n6.count"); printf("\n7.search"); printf("\n8.sort"); printf("\n9.reverse"); printf("\n0.exit"); printf("\nenter your choice"); scanf("%d",&ch); switch(ch) { case 1 : addstart();break; case 2 : addmiddle();break; case 3 : addlast();break; case 4 : deldata();break; case 5 : show();break; case 6 : count();break; case 7 : search();break; case 8 : sort();break; case 9 : reverse(); break; case 0 : break; default:printf("wrong choice");break; } }while(ch!=0); } addstart() { struct node *newnode; newnode=(struct node*)malloc(sizeof(struct node)); printf("enter the data"); scanf("%d",&newnode->data); newnode->next=NULL; newnode->prev=NULL; if(start==NULL) { start=newnode; last=newnode; } else { start->prev=newnode; newnode->next=start; start=newnode; } } addlast() { struct node *newnode; newnode=(struct node*)malloc(sizeof(struct node)); printf("enter the data"); scanf("%d",&newnode->data); newnode->next=NULL; newnode->prev=NULL; if(start==NULL) { start=newnode; last=newnode; } else { last->next=newnode; newnode->prev=last; last=newnode; } } show() { for(p=start;p!=NULL;p=p->next) { printf("%d",p->data); } } count() { int c=0; for(p=start;p!=NULL;p=p->next) { c++; } printf("%d",c); } addmiddle() { int n; struct node *newnode; newnode=(struct node*)malloc(sizeof(struct node)); printf("enter the data"); scanf("%d",&newnode->data); newnode->next=NULL; newnode->prev=NULL; if(start==NULL) { start=newnode; last=newnode; } else { printf("enter data after which u want to add"); scanf("%d",&n); for(p=start;p!=NULL;p=p->next) { if(p->data==n) { p->next->prev=newnode; newnode->next=p->next; newnode->prev=p; p->next=newnode; break; } } } } search() { int n,flag=0,c=0; printf("enter data to search"); scanf("%d",&n); for(p=start;p!=NULL;p=p->next) { if(p->data==n) { flag=1; c++; break; } else c++; } if(flag==1) printf("found on %d",c); else printf("not found"); } deldata() { int n; printf("enter no to delete"); scanf("%d",&n); if(start==NULL) { printf("no data to delete"); } else { for(p=ptr=start;p!=NULL;p=p->next) { if(p->data==n) { if(p==start) { start=p->next; start->prev=NULL; free(p); break; } else if(p==last) { last=p->prev; last->next=NULL; free(p); break; } else { p->next->prev=p->prev; p->prev->next=p->next; free(p); break; } } } } } sort() { int t; p=start; do { ptr=start; do { if(ptr->data>ptr->next->data) { t=ptr->data; ptr->data=ptr->next->data; ptr->next->data=t; } ptr=ptr->next; }while(ptr->next!=NULL); p=p->next; }while(p!=NULL); } reverse() { for(p=last;p!=NULL;p=p->prev) { printf("%d",p->data); } }