Linear Linked list implementation of Queue

Here is the program on linear linked list implementation of queue where insertion and deletion can be performed as required, no limit.

 # include < stdio.h>

# include < stdlib.h>

struct link

{

char info[20];

struct link *next;

};

struct link *p,*node,*new1,*start=NULL;

struct link *insert(struct link *nn)

{

node = nn;

p=NULL;

new1 = (struct link* ) malloc(sizeof(struct link));

while(node)

{

 node=node->next;

 p=p->next;

 }

 p->next=new1;

 new1->next=node;

 fflush(stdin);

printf("\n Input the node value: ");

gets(new1->info);

node=start->next;

return node;

}

void display(struct link *node)

{

    while (node)

{

printf(" %s", node->info);

node = node->next;

}

}

struct link *del(struct link *nn)

{

node=nn;

if(node==NULL)

printf("\nDeletion not possible.");

else

{

p=node->next;

free(node);

node=p;

}

return node;

}

void main()

{

struct link *start=NULL;

int k = 0;

char choice;

clrscr();

do

{

printf("\nInsert->i Delete->d Quit->q:");

printf("\nInput the choice : ");

do

{

choice = getchar();

choice = tolower(choice);

}while(strchr("idq",choice)==NULL);

printf("Your choice is: %c ", choice);

switch(choice)

{

case 'i' :

{

 start=insert(start);

printf("\nQueue after inserting ");

display(start);

break;

}

case 'd' :

{

start=del(start);

printf("\nQueue content after deleteion is as follows:\n");

display(start);

break;

 }

case 'q':

{

k = 1;

}

}

} while(!k);

getch();

}