Queue - Insertion Operation

#include< stdio.h >
#include< conio.h >
//global declaration
int a[20],n,i,rear,front,x;


void main()
{ clrscr();
printf("Enter Total Number of Elements = ");
scanf("%d",&n);
//initialise
rear=0;
front=0;
//insert element
while(rear < n)
{       //check for Overflow
    if(rear > n)
    {
        printf("\nQueue Full");
        exit();
    }
    else
    {
        //enter element
        printf("\nEnter Element a[%d] = ",rear);
        scanf("%d",&x);
        a[rear]=x;
        //reset rear
        rear=rear+1;
    }
}


//Traverse Stack
printf("\n***** Elements of Queue Are ***** \n");
while(i < rear)
{
    printf("_____\n");
    printf("| %d |\n",a[i]);
    i=i+1;
}
printf("_____\n");
getch();
}