feat: Add functions for sorting, finding max/min, sum/average, prime/palindrome checks, and duplicate removal

- Add functions to sort an array of numbers, find the maximum and minimum numbers in an array, find duplicate numbers in an array, remove duplicate numbers from an array, check if a number is prime, check if a string is a palindrome, reverse a string, and reverse a number.
- Implement the functions without using any built-in methods.

Author: manthanank

README.md

@@ -7061,10 +7061,10 @@ JavaScript offers several shorthand techniques to write code more concisely and
 
 ## Interview Questions
 
-Write a function that sorts an array of numbers Without Inbuilt Method.
+Sorts an array of numbers without using any built-in method.
 
 ```javascript
-function sortArray(arr) {
+const sortArray = (arr) => {
   for (let i = 0; i < arr.length; i++) {
     for (let j = i + 1; j < arr.length; j++) {
       if (arr[i] > arr[j]) {
@@ -7075,41 +7075,41 @@ function sortArray(arr) {
     }
   }
   return arr;
-}
+};
 
 const numbers = [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5];
 console.log(sortArray(numbers)); // Output: [1, 1, 2, 3, 3, 4, 5, 5, 5, 6, 9]
 ```
 
-Write a function that finds the maximum number in an array of numbers Without Inbuilt Method.
+Find the maximum number in an array of numbers without using any built-in method.
 
 ```javascript
-function findMax(arr) {
+const findMax = (arr) => {
   let max = arr[0];
   for (let i = 1; i < arr.length; i++) {
     if (arr[i] > max) {
       max = arr[i];
     }
   }
   return max;
-}
+};
 
 const numbers = [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5];
 console.log(findMax(numbers)); // Output: 9
 ```
 
-Write a function that finds the minimum number in an array of numbers Without Inbuilt Method.
+Find the minimum number in an array of numbers without using any built-in method.
 
 ```javascript
-function findMin(arr) {
+const findMin = (arr) => {
   let min = arr[0];
   for (let i = 1; i < arr.length; i++) {
     if (arr[i] < min) {
       min = arr[i];
     }
   }
   return min;
-}
+};
 
 const numbers = [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5];
 console.log(findMin(numbers)); // Output: 1
@@ -7199,76 +7199,90 @@ console.log(isPalindrome('madam')); // Output: true
 console.log(isPalindrome('hello')); // Output: false
 ```
 
-Write a function to find duplicate numbers in an Array Without Inbuilt Method.
+Find duplicate numbers in an array without using any built-in method.
 
 ```javascript
-function findDuplicates(arr) {
-  const duplicates = [];
+const findDuplicates = (arr) => {
+  let duplicates = [];
+  let index = 0;
   for (let i = 0; i < arr.length; i++) {
     for (let j = i + 1; j < arr.length; j++) {
-      if (arr[i] === arr[j] && !duplicates.includes(arr[i])) {
-        duplicates.push(arr[i]);
+      let isDuplicate = false;
+      if (arr[i] === arr[j]) {
+        for (let k = 0; k < index; k++) {
+          if (duplicates[k] === arr[i]) {
+            isDuplicate = true;
+            break;
+          }
+        }
+        if (!isDuplicate) {
+          duplicates[index] = arr[i];
+          index++;
+        }
       }
     }
   }
   return duplicates;
-}
+};
 
-const numbers = [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5];
-console.log(findDuplicates(numbers)); // Output: [1, 3, 5]
+let numbers = [1, 2, 3, 4, 2, 5, 6, 3, 7, 8, 8];
+console.log(findDuplicates(numbers)); // Output: [2, 3, 8]
 ```
 
 [Back to Top⤴️](#table-of-contents)
 
-Write a function to remove duplicate numbers in an Array Without Inbuilt Method.
+Remove duplicate numbers in an array without using any built-in method.
 
 ```javascript
-function removeDuplicates(arr) {
-  const unique = [];
+const removeDuplicates = (arr) => {
+  let unique = [];
+  let index = 0;
+
   for (let i = 0; i < arr.length; i++) {
     let isDuplicate = false;
-    for (let j = 0; j < unique.length; j++) {
+    for (let j = 0; j < index; j++) {
       if (arr[i] === unique[j]) {
         isDuplicate = true;
         break;
       }
     }
     if (!isDuplicate) {
-      unique.push(arr[i]);
+      unique[index] = arr[i];
+      index++;
     }
   }
   return unique;
-}
+};
 
-const numbers = [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5];
-console.log(removeDuplicates(numbers)); // Output: [3, 1, 4, 5, 9, 2, 6]
+let numbers = [1, 2, 3, 4, 2, 5, 6, 3, 7, 8, 8];
+console.log(removeDuplicates(numbers)); // Output: [1, 2, 3, 4, 5, 6, 7, 8]
 ```
 
-Write a function to reverse a string Without Inbuilt Method.
+Reverse a string without using any built-in method.
 
 ```javascript
-function reverseString(str) {
+const reverseString = (str) => {
   let reversed = '';
   for (let i = str.length - 1; i >= 0; i--) {
     reversed += str[i];
   }
   return reversed;
-}
+};
 
 console.log(reverseString('hello')); // Output: 'olleh'
 ```
 
-Write a function to reverse a number Without Inbuilt Method.
+Reverse a number without using any built-in method.
 
 ```javascript
-function reverseNumber(num) {
+const reverseNumber = (num) => {
   let reversed = 0;
   while (num > 0) {
     reversed = reversed * 10 + (num % 10);
     num = Math.floor(num / 10);
   }
   return reversed;
-}
+};
 
 console.log(reverseNumber(12345)); // Output: 54321
 ```