C program to implement queue using doubly linked list

#include<stdio.h>
#include<conio.h>
#define MAXSIZE 50;
#define TRUE 1
#define FALSE 0
struct Node
{
int iData;
struct Node *ptrNext;
};
typedef struct Node DLLNode;
DLLNode *front=NuLL, *rear=NULL;
void fnQInsertion(int iData)
{
DLLNode *ptrNewNode;
ptrNewNode = (DLLNode*) malloc(sizeof(DLLNode));
ptrNewNode->iData=iData;
ptrNewNode->ptrNext=NULL;
if(fnQEmpty()==TRUE)
front=rear=ptrNewNode;
else
{
rear->ptrNext=ptrNewNode;
rear=ptrNewNode;
}
} // End of Algorithm

int fnQDelete()
{
int iData;
DLLNode *ptrDeleteNode;
if(fnQEmpty()== TRUE)
{
printf("\nQueue is Empty\n");
return 0;
}
else
{
iData=front->iData;
ptrDeleteNote=front;
front=front->ptrNext;
free(ptrDeleteNode);
return(iData);
}
} // End of Algorithm

void fnQDisplay()
{
DLLNode *ptrDisplayNode;
if(fnQEmpty()==TRUE)
printf("\nNothing to Display\n");
else
{
ptrDisplayNode=front;
while(ptrDisplayNode!=NULL)
{
printf("%d\n", ptrDisplayNode->iData);
ptrDisplayNode=ptrDisplayNode->ptrNext;
}
}
} // End of Algorithm
int fnQEmpty()
{
if(front==NULL || rear==NULL)
return TRUE;
else
return FALSE;
}

void main()
{
int iChoice, iData;
clrscr();
do
{
printf("1. Insertion\n");
printf("2. Deletion\n");
printf("3. Display\n");
printf("4. Exit\n");
printf("Enter your choice\n");
scanf("%d", &iChoice);
switch(iChoice)
{
case 1:
printf("Enter the element");
scanf("%d", &iData);
fnQInsertion(iData);
break;
case 2:
if(fnQEmpty()==TRUE)
printf("Queue is empty\n");
else
printf("Item is deleted =%d\n", fnQDelete());
break;
case 3:
printf("\n**** Queue Content****\n");
fnQDisplay();
printf("\n***********************\n");
break;
case 4:
exit(1);
default:
printf("\nWrong Choice\n");
}
} while(1);
}