practise is done

src/main/java/school/lemon/changerequest/java/introduction/pr1/Bob.java

@@ -4,7 +4,28 @@
 public class Bob {
 
     public static String hey(String phrase) {
-        return "";
+        char ch;
+        int counter = 0;
+        boolean flag = true;
+        String reply = "";
+        if(phrase == "") return "Fine.";
+
+        for(int i = 0; i < phrase.length(); i++){
+            ch = phrase.charAt(i);
+            if(ch == '?'){
+                reply = "Yeap.";
+            } else if(ch == '!'){
+                reply = "Chill out!";
+            } else if(ch == '.') {
+                reply = "Whatever.";
+            } else if(ch == ' '){
+                counter++;
+            } else continue;
+        }
+        if(counter == phrase.length())
+            reply = "Fine.";
+
+        return reply;
     }
 
 }

src/main/java/school/lemon/changerequest/java/introduction/pr1/ConsoleCalculator.java

@@ -1,9 +1,76 @@
 package school.lemon.changerequest.java.introduction.pr1;
 
+import java.util.Scanner;
 
 public class ConsoleCalculator {
 
     public static void main(String[] args) {
+        System.out.println("Console Calculation");
+        System.out.println("Enter 'add' to perform addition");
+        System.out.println("Enter 'sub' to perform subtraction");
+        System.out.println("Enter 'mul' to perform multiplication");
+        System.out.println("Enter 'div' to perform division");
+        System.out.println("Enter 'exit' to exit");
+        System.out.println("Enter 'help' to see help message");
+        boolean flag = true;
+        while(flag) {
+            System.out.println("Make your choice: ");
+            Scanner read = new Scanner(System.in);
+            String choice = read.next();
+            choice = choice.toLowerCase();
+            switch (choice) {
+                case "add": {
+                    System.out.println("Enter first number: ");
+                    int first = read.nextInt();
+                    System.out.println("Enter second number: ");
+                    int second = read.nextInt();
+                    int res = first + second;
+                    System.out.println("    Result of " + first + "+" + second + " is " + res);
+                    break;
+                }
+                case "sub" : {
+                    System.out.println("Enter first number: ");
+                    int first = read.nextInt();
+                    System.out.println("Enter second number: ");
+                    int second = read.nextInt();
+                    int res = first - second;
+                    System.out.println("    Result of " + first + "-" + second + " is " + res);
+                    break;
+                }
+                case "mul" : {
+                    System.out.println("Enter first number: ");
+                    int first = read.nextInt();
+                    System.out.println("Enter second number: ");
+                    int second = read.nextInt();
+                    int res = first*second;
+                    System.out.println("    Result of " + first + "*" + second + " is " + res);
+                    break;
+                }
+                case "div" : {
+                    System.out.println("Enter first number: ");
+                    int first = read.nextInt();
+                    System.out.println("Enter second number: ");
+                    int second = read.nextInt();
+                    double res = first/second;
+                    System.out.println("    Result of " + first + "/" + second + " is " + res);
+                    break;
+                }
+                case "exit" : {
+                    System.out.println("bye-bye!");
+                    flag = false;
+                    break;
+                }
+                case "help" : {
+                    System.out.println("Enter 'add' to perform addition");
+                    System.out.println("Enter 'sub' to perform subtraction");
+                    System.out.println("Enter 'mul' to perform multiplication");
+                    System.out.println("Enter 'div' to perform division");
+                    System.out.println("Enter 'exit' to exit");
+                    System.out.println("Enter 'help' to see help message");
+                }
+
+            }
+        }
 
     }
 }

src/main/java/school/lemon/changerequest/java/introduction/pr1/HammingDistance.java

@@ -2,6 +2,16 @@
 
 public class HammingDistance {
     public static int compute(String a, String a1) {
-        return -1;
+        int counter = 0;
+        if(a.length() != a1.length()) {
+            return -1;
+        } else {
+            for(int i = 0; i < a.length(); i++){
+                if(a.charAt(i) != a1.charAt(i)){
+                    counter++;
+                }
+            }
+        }
+        return counter;
     }
 }