C Program :
Given coordinates of a point (x,y) and radius of standard circle(having center at origin). 
Write a prog. to check the point is inside, outside or on the circle.

C Programming -->
 
/* PROG. TO CHECK GIVEN POINT IS INSIDE, OUTSIDE OR ON THE STD.
CIRCLE */
#include<stdio.h>
#include<conio.h>
#include<math.h>
main()
{
int r,x,y,d;
clrscr();
printf("enter radius of circle and coordinate of point ");
scanf("%d%d%d II,&r,&x,&y);
d= x*x+y*y; /* distance of point from origin since center is origin */
if(d<=(r*r))
{
if(d«r*r))
printf("points is inside the circle");
else
printf("point is on the circle");
}
else
printf("point is outside the circle");
getch();
}