Added Calculator, finding max_number, and sorting

TDD_for_beginners/Calculator/Calculator.java

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+public class Calculator {
+
+    // Method to add two numbers
+    public int add(int first, int second) {
+        return first + second;
+    }
+
+    // Method to multiply two numbers
+    public int multiply(int first, int second) {
+        return first * second;
+    }
+}

TDD_for_beginners/Calculator/CalculatorTest.java

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+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class CalculatorTest {
+
+    @Test
+    public void testProduct() {
+        // Create an instance of the Calculator class
+        Calculator product = new Calculator();
+
+        // Call the multiply method on the Calculator instance
+        // and store the result in the 'prod' variable
+        int prod = product.multiply(2,4);
+
+        // Check if the result is equal to 8 using the assertEquals method
+        assertEquals(8,prod);
+    }
+
+    @Test
+    public void testAdd() {
+        // Create an instance of the Calculator class
+        Calculator calculator = new Calculator();
+
+        // Call the add method on the Calculator instance
+        // and store the result in the 'result' variable
+        int result = calculator.add(2, 3);
+
+        // Check if the result is equal to 5 using the assertEquals method
+        assertEquals(5, result);
+    }
+}

TDD_for_beginners/Max_number_in_array/Max.java

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+import java.util.Arrays;
+
+public class Max {
+
+    // Array of integers
+    int[] arr = new int[]{1, 2, 3, 4};
+
+    // Method to find the maximum number in an array
+    public int max_num(int[] arr) {
+        int max = 0;
+
+        // Iterate through the array
+        for (int j : arr) {
+            if (max < j) {
+                max = j;
+            }
+        }
+
+        return max;
+    }
+}

TDD_for_beginners/Max_number_in_array/MaxnumberTest.java

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+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class MaxnumberTest {
+
+    @Test
+    // Test case to verify the functionality of max_num method
+    public void textMax() {
+        // Create an instance of the Max class
+        Max max = new Max();
+
+        // Create an array of integers
+        int[] arr = new int[]{1, 2, 3, 4};
+
+        // Call the max_num method on the Max instance
+        // and store the result in the 'max_number' variable
+        int max_number = max.max_num(arr);
+
+        // Check if the result is equal to 4 using the assertEquals method
+        assertEquals(4, max_number);
+    }
+}

TDD_for_beginners/Sorting/Sort.java

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+import java.util.Arrays;
+
+
+public class Sort {
+//There are multiple ways to sort an array
+//Lets move with Bubble sort
+    int[] arr = new int[]{1,2,3,4};
+    public void bubble(int[] arr){
+        for(int i=0; i < arr.length;i++) {
+            for (int j = 1; j < arr.length; j++) {
+                if (arr[j] < arr[j - 1]) {
+                    swap(arr,j, j - 1);
+                }
+            }
+        }
+    }
+
+    private void swap(int[] arr,int first, int second) {
+        int temp = arr[first];
+        arr[first] = arr[second];
+        arr[second] = temp;
+    }
+    }
+

TDD_for_beginners/Sorting/SortingTest.java

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+import org.junit.Test;
+import java.util.Arrays;
+import static org.junit.Assert.*;
+
+public class SortingTest {
+
+    @Test
+    // Test case to verify the functionality of the bubble sort algorithm
+    public void testing() {
+        // Create an instance of the Sort class
+        Sort sort = new Sort();
+
+        // Create an array of integers
+        int[] arr = new int[]{1, 3, 2, 0};
+
+        // Call the bubble method on the Sort instance to sort the array
+        sort.bubble(arr);
+
+        // Print the sorted array to the console
+        System.out.println(Arrays.toString(arr));
+    }
+}