Added a Kotlin variation.

Java/lab_1/lab_1.java

@@ -2,19 +2,16 @@ import java.util.Scanner;
 
 public class lab_1 {
     
-    public static int protectedInput(String variable_to_read, Scanner input) {
-        int read_variable;
+    public static int protectedInput(String variableToRead, Scanner input) {
         do {
             try {
-                System.out.printf("Enter %s: ", variable_to_read);
-                read_variable = input.nextInt();
-                break;
+                System.out.printf("Enter %s: ", variableToRead);
+                return input.nextInt();
             } catch (Exception e) {
-                System.out.printf("%s must be an integer.\n", variable_to_read.toUpperCase());
+                System.out.printf("%s must be an integer.\n", variableToRead.toUpperCase());
                 input.nextLine();
             }
         } while (true);
-        return read_variable;
     }
 
     public static void main(String[] args) {
@@ -27,7 +24,7 @@ public class lab_1 {
 
         input.close();
 
-        float s = ((float) (b + m) / 2) * (m - b + 1) * (n - a + 1);
+        final float s = ((float) (b + m) / 2) * (m - b + 1) * (n - a + 1);
 
         System.out.println("S = " + s);
     }

Java/lab_1/lab_1.kt

@@ -0,0 +1,21 @@
+fun protectedInput(variableName: String): Int {
+    do {
+        try {
+            print("Enter $variableName: ")
+            return readln().toInt()
+        } catch (e: Exception) {
+            println("${variableName.uppercase()} must be an integer!")
+        }
+    } while (true)
+}
+
+fun main() {
+    val n: Int = protectedInput("n")
+    val m: Int = protectedInput("m")
+    val a: Int = protectedInput("a")
+    val b: Int = protectedInput("b")
+
+    val s: Float = (b + m).toFloat() / 2 * (m - b + 1) * (n - a + 1)
+
+    println("S = $s")
+}