Problem Statement

1Problem Description :  
2Write Algorithm, Flowchart and Program to Find Area of a Circle for which Radius is given.  
3 
4Example 1 : 
5
6  Input  : radius is 4 
7  Output : 50.24 
8  Explanation :  Circle area formula is 3.14*radius*radius  
9                 So area = 3.14*4*4 = 50.24 
10
11Example 2 : 
12
13  Input  : radius is 5
14  Output : 78.54
15  Explanation :  Circle area formula is 3.14*radius*radius 
16                 So area = 3.14*5*5 = 78.54

Algorithm

1Input : radius of a circle
2 
3Step 1: Start 
4Step 2: Read radius 
5Step 3: Calculate area, area = 3.14*radius*radius 
6Step 4: Print area 
7Step 5: Stop 
8  
9Output: area

Flowchart

Code Implementation

1import java.util.Scanner;
2
3public class AreaOfACircle {
4
5  public static void main(String[] args) {
6    Scanner sc = new Scanner(System.in);
7
8    // Read radius
9    System.out.print("Enter radius : ");
10    float r = sc.nextFloat();
11
12    // Calculate Area
13    double area = 3.14 * r * r;
14
15    // Print area
16    System.out.printf("Area of circle with radius %f is"
17      + " %f \n", r, area);
18  }
19}

Output 1 :

1Enter radius : 4 
2Area of circle with radius 4.000000 is 50.240000

Output 2 :

1Enter radius : 5 
2Area of circle with radius 5.000000 is 78.500000