Doubly Linked List program in C

#include <stdlib.h> #include <stdio.h> #include <conio.h> struct node { int id; char name[30]; struct node* next; struct node* back; } *start,*ptr,*last; void insert_beg(struct node **start,struct node **last) { struct node * tmp=(struct node*)malloc(sizeof(node)); if(tmp==NULL) { printf("OverFlow\n"); return; } printf("Enter Details Name then id\n"); scanf("%s%d",tmp->name,&tmp->id); if(*start==NULL) { tmp->back=NULL; tmp->next=NULL; *start=tmp; *last=tmp; printf("Succesfully added as First node\n"); return; } tmp->next=*start; tmp->back=NULL; (*start)->back=tmp; *start=tmp; printf("Succesfully added in the Beginning \n"); } /*OUT OF SYLLABUS void insert_last(struct node **start,struct node **last) { struct node * tmp=(struct node*)malloc(sizeof(node)); if(tmp==NULL) { printf("OverFlow\n"); return; } printf("Enter Details Name then id(addition at last)\n"); scanf("%s%d",tmp->name,&tmp->id); if(*start==NULL) { tmp->back=NULL; tmp->next=NULL; *start=tmp; *last=tmp; printf("Succesfully added as first node\n"); return; } tmp->back=*last; tmp->next=NULL; (*last)->next=tmp; *last=tmp; printf("Succesfully added (last) \n"); } void del_beg(struct node **start,struct node **last) { if(*start==NULL) { printf("Underflow,List empty CANT DELETE\n"); return; } if(*start==*last) { printf("Succesfully deleted EK hee node tha(beg)\n"); *last=NULL; free(*start); *start=NULL; return; } struct node *tmp; struct node *delu; tmp=(*start)->next; delu=*start; tmp->back=NULL; *start=tmp; free(delu); (*start)->back=NULL; printf("Succesfully deleted (beg)\n"); } */ void del_last(struct node **start,struct node **last) { if(*start==NULL) { printf("Underflow,List empty CANT DELETE\n"); return; } if(*start==*last) { printf("Succesfully deleted EK hee node tha (last)\n"); *last=NULL; free(*start); *start=NULL; return; } struct node *tmp; struct node *delu; tmp=(*last)->back; delu=*last; tmp->next=NULL; *last=tmp; free(delu); printf("Succesfully deleted (last)\n"); } void disp(struct node **start,struct node **last) { struct node *tmp; tmp=*start; while(tmp!=NULL) { printf("Name = %s then ID = %d\n",tmp->name,tmp->id); tmp=tmp->next; } printf("Done printing\n"); } int main() { start=last=NULL; int con,ch,what; do { printf("Menu Driven ---> \n Enter 1 to Insert\t Enter 2 to Delete\n Enter 3 to Display\n"); scanf("%d",&ch); switch(ch) { case 1:{ printf("1 for Beginning\t2 for End\tINSERT\n"); scanf("%d",&what); if(what==1) { insert_beg(&start,&last); } else { printf("Error Out of Syllabus\n"); //insert_last(&start,&last); } printf("Out of insertion\n"); break; } case 2:{ printf("1 for Beginning\t 2 for End\t DELETE\n"); scanf("%d",&what); if(what==1) { printf("Error Out of Syllabus\n"); //del_beg(&start,&last); } else { del_last(&start,&last); } printf("Out of deletion\n"); break; } case 3:{ printf("Display\n"); disp(&start,&last); printf("Out of Display\n"); break; } } printf("Enter 1 to continue\n"); scanf("%d",&con); }while(con==1); printf("End of prog..\n"); return 0; }

Program for doubly linked list