Program to reverse sentence word by word using C#

eXclusiveMinds — Tue, 08 Dec 2009 18:40:21 +0000

This example shows how can we reverse a sentence word by word. For example; If we have string “This is an eXclusiveMinds article” output should be “article eXclusiveMinds an is This”. For this we have two methods ReverseWordByWord and Reverse (this is helper method to reverse string character by character).
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/// 
/// Function to reverse sentence word by word
/// 
/// string (sentence)
/// reversed string by word
public string ReverseWordByWord(string sentence)
{
	char[] str = sentence.ToCharArray();
 
	str = Reverse(str, 0, str.Length - 1);
 
	int start = 0, end = 0;
	for (int i = 0; i < str.Length; i++)
	{
		if (str[i] == ' ')
		{
			end = i - 1;
			str = Reverse(str, start, end);
			start = i + 1;
		}
	}
 
	//For Last word
	end = str.Length - 1;
	str = Reverse(str, start, end);
 
	return new string(str);
}

This method is helper function which will reverse a string character by character.

/// 
/// Helper method to reverse string character by character.
/// 
/// string to be reversed
/// start index
/// end index
/// reversed string
public char[] Reverse(char[] str, int start, int end)
{
	while (end > start)
	{
		str[start] ^= str[end];
		str[end] ^= str[start];
		str[start] ^= str[end];
		end--;
		start++;
	}
	return str;
}

Testing This Method:

string output=ReverseWordByWord("This is an eXclusiveMinds article");
Console.WriteLine(output);

OUTPUT:

//input: This is an eXclusiveMinds article
article eXclusiveMinds an is This

eXclusiveMinds » Sentence Reverse

Program to reverse sentence word by word using C#