Question

PLESE CODE IN C# not java

RECURSION

Objectives

• Learn the basics of recursion – Part II (last week was Part I) Submission Guidelines:

You will turn in 2 program files (one for each lab problem)

Tasks

This lab has two parts:

Write a driver program that calls this method from the Main program.

• •

Write a driver program that calls this method from the Main program.

Note: Your program name should match the name of your java / C# class exactly. e.g Lab10a.java / Lab10a.cs

Sample Output: LAB 1:

//A call to recursive function repeatNTimes(“hello”, 5) hellohellohellohellohello

// A call to recursive function repeatNTimes(“Good morning!”, 3) Good morning!Good morning!Good morning!

LAB 2:

1. Write a recursive method

repeatNTimes(String s, int n) that accepts a String and an

integer as two parameters and returns a string that is concatenated together n times. (For

example, repeatNTimes ("hello", 3) returns "hellohellohello")

2. Write a recursive method called isReverse(String s1, String s2) that accepts two

strings as parameters and returns true if the two strings contain the same sequence of characters as

each other but in the opposite order and false otherwise.

The recursive function should ignore capitalization. (For example, the call of

isReverse("hello", "eLLoH") would return true.)

The empty string, as well as any one letter string, should be its own reverse.

  

Page 1 of 2

//Call to recursive function isReverse ("Computer","retupmCo") false

//Call to recursive function isReverse ("Hello","olleh") true

Answer 1

Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. If not, PLEASE let me know before you rate, I’ll help you fix whatever issues. Thanks

/*Program 1*/

//Lab10a.cs

using System;

class Lab10a{
        //method to return a string containing s repeated n times
        public static String repeatNTimes(String s, int n){
                //if n is 0 or below, returning empty string
                if(n<=0){
                        return "";
                }else{
                        //else returning s concatenated with the value returned from 
                        //recursive call passing n-1 as new n
                        return s+repeatNTimes(s,n-1);
                }
        }
        //Main method for testing
        public static void Main(String[] args){
                Console.WriteLine(repeatNTimes("hello", 5));
                Console.WriteLine(repeatNTimes("Good morning!", 3));
                
                //wait for a key press to quit. remove if not needed.
                Console.ReadKey();
        }
}

/*OUTPUT */

hellohellohellohellohello
Good morning!Good morning!Good morning!

/*Program 2*/

//Lab10b.cs

using System;

class Lab10a{
        //method to check if s1 is same as s2, but in reverse
        public static bool isReverse(String s1, String s2){
                //if lengths of s1 an s2 mismatch, returning false
                if(s1.Length!=s2.Length){
                        return false;
                }
                //if strings are empty, returning true
                else if(s1.Length==0){
                        return true;
                }
                //comparing first char of s1 with last char of s2, after converting them to 
                //lower case
                if(Char.ToLower(s1[0])!=Char.ToLower(s2[s2.Length-1])){
                        //mismatch s1 is not reverse of s2
                        return false;
                }
                //otherwise removing first char from s1, last char from s2, calling method 
                //recursively passing new strings
                //note: s1.Substring(1) will return a s1 without first character
                // s2.Substring(0,s2.Length-1) will return s2 without last character
                return isReverse(s1.Substring(1),s2.Substring(0,s2.Length-1));
        }
        
        //Main method for testing
        public static void Main(String[] args){
                Console.WriteLine(isReverse ("Computer","retupmCo"));
                Console.WriteLine( isReverse ("Hello","olleh") );
                
                //wait for a key press to quit. remove if not needed.
                Console.ReadKey();
        }
}

/*OUTPUT*/

False
True