WAP to Reverse String Without Affecting Digits Position

WAP to Reverse String Without Affecting Digits Position: In this program InterviewPrograms48, we are reversing the non-numeric substrings within a given string while leaving the numeric substrings unchanged.

Reverse String Without Affecting Digits Position

package com.softwaretestingo.interviewprograms;
public class InterviewPrograms48 
{
	/*
	 * Input string : test986java656hello 
	 * Output : tset986avaj656olleh
	 */
	public static void main(String[] args) 
	{
		String str="test986java656hello";
		disp(str);
	}
	public static void disp(String str)
	{
		String[] strarr=str.split("(?<=\\D)(?=\\d)|(?<=\\d)(?=\\D)");
		for (int i=0;i<strarr.length;i++)
		{
			if(! Character.isDigit(strarr[i].charAt(0)))
			{
				strarr[i]=rev(strarr[i]);
			}
		}


		String s2=String.join("", strarr);
		System.out.println(s2);
	}

	public static String rev(String str) 
	{
		String rev="";
		for(int i=str.length()-1;i>=0;i--)
		{
			rev=rev+str.charAt(i);
		}
		return rev;
	}
}

Output

tset986avaj656olleh

Here’s a step-by-step explanation of the program:

1. public static void main(String[] args): This is the entry point of the program. It starts by defining the input string “test986java656hello”.
2. disp(str): The program calls the disp method and passes the input string as an argument.
3. String[] strarr = str.split(“(?<=\\D)(?=\\d)|(?<=\\d)(?=\\D)”);: The input string is split into an array of substrings using regular expressions. The regular expression (?<=\\D)(?=\\d)|(?<=\\d)(?=\\D) matches the boundary between a non-digit and a digit, or the boundary between a digit and a non-digit. This splits the string into segments of continuous non-digits and digits.
4. for (int i = 0; i < strarr.length; i++): The program iterates through each segment in the strarr array.
5. if (!Character.isDigit(strarr[i].charAt(0))): If the first character of the segment is a non-digit, the program enters the if condition.
6. strarr[i] = rev(strarr[i]);: The program calls the rev method and passes the segment as an argument. The rev method reverses the characters in the segment.
7. String s2 = String.join(“”, strarr);: The program joins the modified segments back into a single string, using an empty string as the delimiter.
8. System.out.println(s2);: The program prints the resulting string, which is the input string with non-digit segments reversed.

By the end of the program, the output is obtained as “tset986avaj656olleh”, where the non-digit segments in the input string are reversed while the digit segments remain unchanged.