Java: Test if circumference of two circles intersect or overlap

Last update on May 13 2025 12:58:57 (UTC/GMT +8 hours)

Test Relationship Between Two Circles

There are two circles C1 with radius r1, central coordinate (x1, y1) and C2 with radius r2 and central coordinate (x2, y2).
Write a Java program to test the followings -
"C2 is in C1" if C2 is in C1
"C1 is in C2" if C1 is in C2
"Circumference of C1 and C2 intersect" if circumference of C1 and C2 intersect, and
"C1 and C2 do not overlap" if C1 and C2 do not overlap.

Input:
Input numbers (real numbers) are separated by a space.

Visual Presentation:

Sample Solution:

Java Code:

// Importing the Scanner class for user input
import java.util.Scanner;

// Main class named "Main"
public class Main {
    // Main method to execute the program
	public static void main(String arg[]) {
		// Creating a Scanner object for user input
		Scanner in = new Scanner(System.in);

		// Prompting the user to input x1, y1, and r1 for the first circle
		System.out.println("Input x1, y1, r1: (numbers are separated by a space)");
		double x1 = in.nextDouble(), y1 = in.nextDouble(), r1 = in.nextDouble();

		// Prompting the user to input x2, y2, and r2 for the second circle
		System.out.println("Input x2, y2, r2: (numbers are separated by a space)");
		double x2 = in.nextDouble(), y2 = in.nextDouble(), r2 = in.nextDouble();

		// Calculating the distance between the centers of the two circles
		double l = Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));

		// Checking the relationship between the circles based on their radii and distance
		if (l > r1 + r2)
			System.out.println("Circumference of C1 and C2 intersect");
		else if (r1 > l + r2)
			System.out.println("C2 is in C1");
		else if (r2 > l + r1)
			System.out.println("C1 is in C2");
		else
			System.out.println("C1 and C2 do not overlap");
	}
} 

Sample Output:

Input x1, y1, r1: (numbers are separated by a space)
 5 6 8 7
Input x2, y2, r2: (numbers are separated by a space)
 8 9 5 4
C1 and C2  do not overlap

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Java program to determine if two circles are externally tangent, internally tangent, or overlapping.
• Write a Java program to check if one circle completely encloses another circle.
• Write a Java program to test whether the areas of two intersecting circles are equal.
• Write a Java program to compute the distance between two circle centers and determine their positional relationship.

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• Java Basic Part-II Programming Exercises Home ↩
• Java Exercises Home ↩

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