CC-16 : Reverse String.

Description:

Given an input String, reverse the characters of the same and return String with reversed characters.

Test cases and expected outputs:

Input Parameters	Expected outputs
Original String: receive	Reversed String: eviecer
Reversed String: red	Reversed String: der

Pseudocode:

reverseString(str):

If str.length==0:

o return str.

Else :

Set variable reversedChar to first character of the String.

Set variable reducedString to str with first character removed.

o Return string collated by appending return value from reverseString(reducedString) and variable reversedChar.

Code:

public String reverseString(String str) {
	if (str.length() == 0) {
		return str;
	}else {
		char reversedChar=str.charAt(0);
		String reducedStr=str.substring(1);
		return reverseString(reducedStr)+reversedChar;
	}
		
}

Click here to download and run code and test cases !

Below fully running code can be copied and run on Eclipse or other Java IDEs. Refer the classname in code below. If the class name below is "A", save the code below to a file named A.java before running it. Be sure to try your own test cases to enhance your understanding ! You can also tweak the code to optimize or add enhancements and custom features.

public class RecursionReverseString {

public String reverseString(String str) {
	if (str.length() == 0) {
		return str;
	}else {
		char reversedChar=str.charAt(0);
		String reducedStr=str.substring(1);
		return reverseString(reducedStr)+reversedChar;
	}
		
}

public static void main(String[] args) {
	/************************
	 Test cases given below:
	 ***********************/
	String retVal;
	try {
	
	RecursionReverseString rcn=new RecursionReverseString();
	String str="receive";
	retVal=rcn.reverseString(str);
	System.out.println("Original String: "+str);
	System.out.println("Reversed String: "+retVal);	
	
	str="";
	retVal=rcn.reverseString(str);
	System.out.println("Original String: "+str);
	System.out.println("Reversed String: "+retVal);		
	
	}catch (Exception exception) {
		System.out.print("Exception: "+ exception);
		exception.printStackTrace();
	}
		
}

}