Put spaces between words starting with capital letters (original) (raw)

Last Updated : 23 Jul, 2025

You are given an array of characters which is basically a sentence. However, there is no space between different words and the first letter of every word is in uppercase. You need to print this sentence after following amendments:

1. Put a single space between these words.
2. Convert the uppercase letters to lowercase.

**Examples:

Input : BruceWayneIsBatman
Output : bruce wayne is batman
Input : You
Output : you

We check if the current character is in uppercase then print " "(space) and convert it into lowercase.

**Implementation:

C++ `

// C++ program to put spaces between words starting // with capital letters. #include using namespace std;

// Function to amend the sentence void amendSentence(string str) { // Traverse the string for(int i=0; i < str.length(); i++) { // Convert to lowercase if its // an uppercase character if (str[i]>='A' && str[i]<='Z') { str[i]=str[i]+32;

        // Print space before it
        // if its an uppercase character
        if (i != 0)
            cout << " ";

        // Print the character
        cout << str[i];
    }

    // if lowercase character
    // then just print
    else
        cout << str[i];
}

}

// Driver code int main() { string str ="BruceWayneIsBatman"; amendSentence(str); return 0; }

Java

// Java program to put spaces between words starting // with capital letters.

import java.util.; import java.lang.; import java.io.*;

class AddSpaceinSentence { // Function to amend the sentence public static void amendSentence(String sstr) { char[] str=sstr.toCharArray();

    // Traverse the string
    for (int i=0; i < str.length; i++)
    {
        // Convert to lowercase if its
        // an uppercase character
        if (str[i]>='A' && str[i]<='Z')
        {
            str[i] = (char)(str[i]+32);
            
            // Print space before it
            // if its an uppercase character
            if (i != 0)
                System.out.print(" ");

            // Print the character
            System.out.print(str[i]);
        }

        // if lowercase character
        // then just print
        else
        System.out.print(str[i]);
    }
}     

// Driver Code
public static void main (String[] args) 
{
    String str ="BruceWayneIsBatman";
    amendSentence(str);
}

}

Python3

Python3 program to put spaces between words

starting with capital letters.

Function to amend the sentence

def amendSentence(string): string = list(string)

# Traverse the string
for i in range(len(string)):

    # Convert to lowercase if its
    # an uppercase character
    if string[i] >= 'A' and string[i] <= 'Z':
        string[i] = chr(ord(string[i]) + 32)

        # Print space before it
        # if its an uppercase character
        if i != 0:
            print(" ", end = "")

        # Print the character
        print(string[i], end = "")

    # if lowercase character
    # then just print
    else:
        print(string[i], end = "")

Driver Code

if name == "main": string = "BruceWayneIsBatman" amendSentence(string)

This code is contributed by

sanjeev2552

C#

// C# program to put spaces between words // starting with capital letters. using System;

public class GFG {

// Function to amend the sentence
public static void amendSentence(string sstr)
{
    char[] str = sstr.ToCharArray();
    
    // Traverse the string
    for (int i = 0; i < str.Length; i++)
    {
        
        // Convert to lowercase if its
        // an uppercase character
        if (str[i] >= 'A' && str[i] <= 'Z')
        {
            str[i] = (char)(str[i] + 32);
            
            // Print space before it
            // if its an uppercase
            // character
            if (i != 0)
                Console.Write(" ");

            // Print the character
            Console.Write(str[i]);
        }

        // if lowercase character
        // then just print
        else
            Console.Write(str[i]);
    }
} 

// Driver Code
public static void Main () 
{
    string str ="BruceWayneIsBatman";
    
    amendSentence(str);
}
    

}

// This code is contributed by Sam007.

JavaScript

`

Output

bruce wayne is batman

**Time complexity: **O(n)
**Auxiliary Space: O(1)

Put spaces between words starting with capital letters using Regex.

C++ `

// C++ Program to solve the above problem #include <bits/stdc++.h> using namespace std;

// Function to insert spaces between words void putSpace(string input) { // Define a regex pattern to match words // starting with a capital letter regex pattern("[A-Z][a-z]*"); smatch match; vector words;

// Find all matches using regex
while (regex_search(input, match, pattern)) {
    words.push_back(match.str());
    input = match.suffix();
}

// Change the first letter of each word to lowercase
for (int i = 0; i < words.size(); i++) {
    words[i][0] = tolower(words[i][0]);
}

// Print the words with spaces
for (int i = 0; i < words.size(); i++) {
    cout << words[i] << " ";
}
cout << endl;

}

// Driver program int main() { string input = "BruceWayneIsBatman"; putSpace(input); return 0; }

// THIS CODE IS CONTRIBUTED BY KIRTI AGARWAL

Java

// Java code for the above approach import java.util.ArrayList; import java.util.List; import java.util.regex.Matcher; import java.util.regex.Pattern;

class GFG { // Function to insert spaces between words public static void putSpace(String input) { // Define a regex pattern to match words starting with a capital letter Pattern pattern = Pattern.compile("[A-Z][a-z]*"); Matcher matcher = pattern.matcher(input); List words = new ArrayList<>();

    // Find all matches using regex
    while (matcher.find()) {
        words.add(matcher.group());
    }

    // Change the first letter of each word to lowercase
    for (int i = 0; i < words.size(); i++) {
        String word = words.get(i);
        words.set(i, word.substring(0, 1).toLowerCase() + word.substring(1));
    }

    // Print the words with spaces
    for (String word : words) {
        System.out.print(word + " ");
    }
    System.out.println();
}

// Driver program
public static void main(String[] args) {
    String input = "BruceWayneIsBatman";
    putSpace(input);
}

} // This code is contributed by Kirti Agarwal

Python3

import re

def putSpace(input):

# regex [A-Z][a-z]* means any string starting
# with capital character followed by many
# lowercase letters
words = re.findall('[A-Z][a-z]*', input)

# Change first letter of each word into lower
# case
for i in range(0, len(words)):
    words[i] = words[i][0].lower()+words[i][1:]
print(' '.join(words))

Driver program

if name == "main": input = 'BruceWayneIsBatman' putSpace(input)

C#

using System; using System.Collections.Generic; using System.Text.RegularExpressions;

public class GFG { // Function to insert spaces between words // Define a regex pattern to match words starting with a capital letter public static void PutSpace(string input) { Regex pattern = new Regex("[A-Z][a-z]*"); Match match; List words = new List();

    // Find all matches using regex
    while ((match = pattern.Match(input)).Success)
    {
        words.Add(match.Value);
        input = input.Substring(match.Index + match.Length);
    }

    // Change the first letter of each word to lowercase
    for (int i = 0; i < words.Count; i++)
    {
        char[] wordChars = words[i].ToCharArray();
        wordChars[0] = char.ToLower(wordChars[0]);
        words[i] = new string(wordChars);
    }

    // Print the words with spaces
    foreach (string word in words)
    {
        Console.Write(word + " ");
    }
    Console.WriteLine();
}

// Driver program
public static void Main(string[] args)
{
    string input = "BruceWayneIsBatman";
    PutSpace(input);
}

}

JavaScript

function putSpace(input) { // regex [A-Z][a-z]* means any string starting // with capital character followed by many // lowercase letters const regex = new RegExp('[A-Z][a-z]*', 'g'); const words = input.match(regex);

// Change first letter of each word into lower // case for (let i = 0; i < words.length; i++) { words[i] = words[i][0].toLowerCase() + words[i].substring(1); }

console.log(words.join(' ')); }

// Driver program const input = 'BruceWayneIsBatman'; putSpace(input);

`

Output

bruce wayne is batman

Time complexity: O(n)
Auxiliary Space: O(n)