C Language Basics

Doubly Linked List Program /*doubly linked List*/ #include #include #include struct node { int no; struct node *next; struct node *prev; }; /* delete at the given location*/ void deletenode(struct node **q,int num) { /*Deleting Node Strategy: First:Check IF it is not null if node found check wheather first element or last lement then delete node else make copy at temp of previous node move forward */ struct node *s,*temp; s=*q; while(s!=NULL) { if(s->no==num) { if(s==*q) { //Directly deal with original node and move to next (*q)=(*q)->next; //s->prev=NULL; break; } else { temp->next=s->next; s->next->prev=temp; break; } if(s->next==NULL) { free(s); s=temp; break; } } else { temp=s; s=s->next; } } } void append(struct node **q,int num) { struct node *s,*newnode; s=*q; if(*q==NULL) { printf("Inserting First eeLEMENT"); *q=(struct node*)malloc(sizeof(struct node*)); (*q)->no=num; (*q)->next=NULL; (*q)->prev=NULL; } else { while(s->next!=NULL) { s=s->next; } newnode=(struct node*)malloc(sizeof(struct node*)); newnode->no=num; newnode->next=NULL; s->next=newnode; } } void print(struct node *s) { printf("\n\tPrinting..."); while(s!=NULL) { printf("\t%d",s->no); s=s->next; } } void main() { struct node *s; s=NULL; clrscr(); append(&s,5); append(&s,67); append(&s,57); printf("\n\tBefore"); print(s); deletenode(&s,5); printf("\n\tAfter..."); print(s); getch(); }