C program to implement Queue using Function

#include<stdio.h>
#include<windows.h>
#include<conio.h>
#define SIZE 5
int insert();
int deletedata();
int display();
struct Queue
{
int queue[SIZE];
int front, rear;
}s;
int main()
{
s.front=0;
s.rear=0;
int ch;
while(1)
{
  printf("\n1.Insert Data\n2.Delete Data\n3.Display Data\n4.Exit\n\t");
  printf("Enter your choice : ");
  scanf("%d", &ch);
  switch(ch)
  {
case 1:
insert();
break;
case 2:
deletedata();
break;
case 3:
display();
break;
case 4:
system("exit");
break;
default:
printf("Invalid Choice ");
}
  }
getch();
}
int insert()
{
int n;
if(s.front==(SIZE-1))
printf("Queue Is full");
else
{
printf("Enter the element : ");
scanf("%d",&n);
s.queue[s.rear]=n;
s.rear++;
}
}
int deletedata()
{
int n;
if(s.front==s.rear)
printf("The Queue is Empty ");
else
{
printf("Enter the element to be deleted ");
scanf("%d", &n);
n=s.queue[s.front];
printf("Deleted Element is %d",s.queue[s.front]);
s.front++;
}
}
int display()
{int i;
if(s.front==s.rear)
printf("The queue is Empty");
else
{
printf("The elements of Queue are : ");
for(i=s.front;i<s.rear;i++)
printf("%d",s.queue[i]);
}
}