Method exercises

Methods/src/Circle.java

@@ -1,5 +1,33 @@
+import java.util.Scanner;
 
 public class Circle {
 	//todo: add some methods to compute a circle's diameter, circumference and area.
 	//print some outputs to confirm you methods are working right.
+	public static double diameter(double r) {
+		double d = 2 * r;
+		return  d;
+	}
+
+	public static double circ(double r) {
+		double pi = Math.PI ;
+		double c = 2 * pi * r ;
+		return c ;
+	}
+
+	public static double area(double r) {
+		double pi = Math.PI ;
+		double a = pi * r * r ;
+		return a ;
+	}
+
+	public static void main(String[] args) {
+
+		Scanner scan = new Scanner(System.in);
+		System.out.println("Radius: ");
+		Double r = scan.nextDouble();
+
+		System.out.println(diameter(r));
+		System.out.println(circ(r));
+		System.out.println(area(r));
+	}
 }

Methods/src/Prime.java

@@ -3,9 +3,30 @@
 
 public class Prime {
 
+	public static boolean prime(int n) {
+
+		if (n <= 1) {
+			return false;
+		} else if (n <= 3 ) {
+			return true;
+		} else if (n % 2 == 0 || n % 3 == 0) {
+			return false;
+		} else {
+			for (int i = 5; i * i <= n; i = i + 6 ) {
+				if (n % i == 0 || n % (i + 2) == 0) {
+					return false; 
+				}
+			return true;
+			} 
+		} return true; 
+	}
+
 	public static void main(String[] args) {
+
 		Scanner scan = new Scanner(System.in);
+		int n = scan.nextInt(); 
 
+		System.out.println("The number " + n + " is prime: " + prime(n));
 		//todo: write a method which tells you if a given number is a prime or not
 
 	}

Structures/src/AssignGrade.java

@@ -6,7 +6,16 @@ public class AssignGrade {
 
 	public static void main(String[] args) {
 		Scanner scan = new Scanner(System.in);
+		System.out.println("Score: ");
+		int score = scan.nextInt();
 
+		double grade = ((100 - score)/50.0) * 3 + 1;
+
+		 if (grade <= 4.0) {
+			System.out.println("Pass with grade: " + grade);
+		} else {
+			System.out.println("Fail with grade: " + grade);
+		} 
 		//todo: when executing the program you will be ask to write a score.
 		//The program converts the score then into a grade and prints that grade (1.0, 1.3, 1.7, ...)
 		//Note that the student passed when the student gets a score of 50.0 points (4.0)

Structures/src/EvenOdd.java

@@ -6,6 +6,16 @@ public class EvenOdd {
 
 	public static void main(String[] args) {
 		Scanner scan = new Scanner(System.in);
+		System.out.println("Number: ");
+		int number = scan.nextInt();
+
+
+		for (int count = 0; count < number; count ++) {
+			if (count % 2 != 0) {
+				System.out.println(count);
+			}
+		}
+
 
 		//todo: The program takes a number as input.
 		//It then goes through all integer values till reaching that value and prints all the odd ones.