C++ String Exercises: Reverse the words of three or more lengths in a string

Last update on April 11 2025 12:47:35 (UTC/GMT +8 hours)

32. Reverse Words of Length Three or More in a String

Write a C++ program that takes a string and reverses the words of three or more lengths in a string. Return the updated string. As input characters, only spaces and letters are permitted.

Sample Data:
("The quick brown fox jumps over the lazy dog") -> “ehT kciuq nworb xof spmuj revo eht yzal god”
("Reverse the words of three or more") -> “esreveR eht sdrow of eerht or erom”
("ABcDef") -> “feDcBA”

Sample Solution:

C++ Code:

#include <bits/stdc++.h> // Include all standard libraries

using namespace std; // Using the standard namespace

// Function to reverse words of three or more lengths in a string
string test(string text) {
	int i = 0; // Initializing variable i to 0
	int l = text.size(); // Getting the size of the input string

	// Loop through the string
	while (i < l) {
		// Find the position of the space character starting from index i
		size_t j = text.find(' ', i);
		// If space character is not found, assign j as the end of string index
		if (j == text.npos) j = l;

		// If the length of the word is three or more, reverse the characters in the word
		if (i + 3 <= j) 
			std::reverse(&text[i], &text[j]);

		i = j + 1; // Move to the next word by updating the starting index i
	}
	return text; // Return the modified string
}

int main() {
	//string text = "The quick brown fox jumps over the lazy dog"; // Test string 1
	//string text ="ABcDef"; // Test string 2
	string text = "Reverse the words of three or more"; // Test string 3
	cout << "Original string: " << text; // Display the original string
	cout << "\n\nReverse the words of three or more lengths of the said string:\n";
	cout << test(text) << endl; // Call the function to reverse words of three or more lengths and display the modified string
}

Sample Output:

Original string: The quick brown fox jumps over the lazy dog

Reverse the words of three or more lengths of the said string:
ehT kciuq nworb xof spmuj revo eht yzal god

Flowchart:

For more Practice: Solve these Related Problems:

• Write a C++ program to reverse only the words in a string that are three or more characters long.
• Write a C++ program that reads a sentence and reverses words exceeding a specified length while preserving short words.
• Write a C++ program to output a string where each word with three or more letters is reversed, leaving others intact.
• Write a C++ program that processes a sentence and alternates the order of letters for words with length greater than or equal to three.

C++ Code Editor:

Click to Open Editor

Contribute your code and comments through Disqus.

Previous C++ Exercise: Check whether a string is uppercase or lowercase.