queue program in c

#include
#include
int queue[10];
int rear=-1;
int front=-1;
void main()
{
int ch;
clrscr();
do
{
printf("**********MAIN MENU***********");
printf("\n1.insert");
printf("\n2.deletedata");
printf("\n3.show");
printf("\n4.exit");
printf("\nenter your choice ");
scanf("%d",&ch);
switch(ch)
{
case 1 : insert();break;
case 2 : deletedata();break;
case 3 : show();break;
case 4 : break;
default : printf("wrong choice");break;
}
}while(ch!=4);
}
insert()
{
int n;
printf("enter the data");
scanf("%d",&n);
if(rear==9)
{
printf("queue is overflow");
}
else if(rear==-1)
{
rear++;
front++;
queue[rear]=n;
}
else
{
rear++;
queue[rear]=n;
}
}
deletedata()
{
if(front==-1)
{
printf("queue empty");
}
else if(rear==front)
{
rear=-1;
front=-1;
}
else
{
front++;
}
}
show()
{
int i;
for(i=front;i<=rear;i++)
{
printf("%d",queue[i]);
}
}