Reverse a given sentence in Java

Question

Can anyone tell me how to write a Java program to reverse a given sentence?

For example, if the input is:

"This is an interview question"

The output must be:

"question interview an is this"

Answer 1

You split the string by the space then iterate over it backwards to assemble the reversed sentence.

String[] words =  "This is interview question".split(" ");

String rev = "";
for(int i = words.length - 1; i >= 0 ; i--)
{
   rev += words[i] + " ";
}

// rev = "question interview is This "

// can also use StringBuilder:
StringBuilder revb = new StringBuilder();
for(int i = words.length - 1; i >= 0 ; i--)
{
   revb.append(words[i]);
   revb.append(" ");
}
// revb.toString() = "question interview is This "

Answer 2

String[] words = sentence.split(" ");
String[] reversedWords = ArrayUtils.reverse(words);
String reversedSentence = StringUtils.join(reversedWords, " ");

(using ArrayUtils and StringUtils from commons-lang, but these are easy methods to write - just a few loops)