Added Java calculation function

Java Code/SimpleCalculator.java

@@ -0,0 +1,56 @@
+import java.util.Scanner;
+
+public class Main {
+  public static void main(String[] args) {
+
+    char operator;
+    Double number1, number2, result;
+
+    // create an object of Scanner class
+    Scanner input = new Scanner(System.in);
+
+    // ask users to enter operator
+    System.out.println("Choose an operator: +, -, *, or /");
+    operator = input.next().charAt(0);
+
+    // ask users to enter numbers
+    System.out.println("Enter first number");
+    number1 = input.nextDouble();
+
+    System.out.println("Enter second number");
+    number2 = input.nextDouble();
+
+    switch (operator) {
+
+      // performs addition between numbers
+      case '+':
+        result = number1 + number2;
+        System.out.println(number1 + " + " + number2 + " = " + result);
+        break;
+
+      // performs subtraction between numbers
+      case '-':
+        result = number1 - number2;
+        System.out.println(number1 + " - " + number2 + " = " + result);
+        break;
+
+      // performs multiplication between numbers
+      case '*':
+        result = number1 * number2;
+        System.out.println(number1 + " * " + number2 + " = " + result);
+        break;
+
+      // performs division between numbers
+      case '/':
+        result = number1 / number2;
+        System.out.println(number1 + " / " + number2 + " = " + result);
+        break;
+
+      default:
+        System.out.println("Invalid operator!");
+        break;
+    }
+
+    input.close();
+  }
+}

Java Code/areaRectangle.java

@@ -0,0 +1,14 @@
+import java.util.Scanner;
+public class AreaOfRectangle {
+   public static void main (String[] args)
+   {
+	   Scanner scanner = new Scanner(System.in);
+	   System.out.println("Enter the length of Rectangle:");
+	   double length = scanner.nextDouble();
+	   System.out.println("Enter the width of Rectangle:");
+	   double width = scanner.nextDouble();
+	   //Area = length*width;
+	   double area = length*width;
+	   System.out.println("Area of Rectangle is:"+area);
+   }
+}