Circle exercise - Hold1 - ugeseddel for første lektion

/**
 CIRCLE.C   Exercise solution 1.7.
 **/

#include <stdio.h>

int main(void) {  
  
  float radius = -1.0; 
  float x = 0.0;
  float y = 0.0;
  int status = 0;

  while (radius < 0.0) {
    printf("\nEnter radius: ");
    scanf("%f",&radius);
  }

  printf("\nEnter the x coordinate: ");
  scanf("%f",&x);
  printf("\nEnter the y coordinate: ");
  scanf("%f",&y);

  if (x*x + y*y <= radius*radius) {
    printf("\nInside!\n");
  }
  if (x*x + y*y > radius*radius) {
    printf("\nOutside!\n");
  }
  
   return status;    

} 

	float radius = -1.0; float x = 0.0; float y = 0.0; int status = 0;
	Declaration of variables. radius is initialized to -1, such that the while-loop will be executed at least once.

 

	while (radius < 0.0) { printf("\nEnter radius: "); scanf("%f",&radius); }
	Data is entered using a while loop, such that if the user enters a negative radius, the program will ask again.

 

	printf("\nEnter the x coordinate: "); scanf("%f",&x); printf("\nEnter the y coordinate: "); scanf("%f",&y);
	The user of the program is asked to enter point coordinates

 

	if (x*x + y*y <= radius*radius) { printf("\nInside!\n"); } if (x*x + y*y > radius*radius) { printf("\nOutside!\n"); }
	Calculate whether the point is inside (or on the boundary of) the circle. We use the equation for a circle, x2 + y2 = r2, to detrmine whether the distance between the point and the center is less than or equal to the radius. It is OK in C to evaluate such an expression where it is needed, in this case just when the if-statement is evaluated.

 

	return status;
	Terminate program