Why Is My Java String Word Reverse Implementation Returning Incorrect Results?

What might cause my Java program that reverses words in a string to give incorrect results?

String reverseWords(String str) { /* Code here */ }

When implementing a word reversal function in Java, common pitfalls can lead to incorrect outputs. Understanding string manipulation and ensuring correct logic flow are key to resolving these issues.

public String reverseWords(String s) { String[] words = s.trim().split("\s+"); StringBuilder reversed = new StringBuilder(); for (int i = words.length - 1; i >= 0; i--) { reversed.append(words[i]); if (i != 0) { reversed.append(" "); } } return reversed.toString(); }

Causes

• Improper handling of spaces between words and at the ends of the string.
• Mistakes in the logic used to rearrange the words.
• Failure to account for punctuation when reversing sentences containing special characters.

Solutions

• Trim the input string to remove leading or trailing spaces before processing it.
• Split the string by spaces and then reverse the array of words to reconstruct the sentence.
• Utilize StringBuilder for efficient concatenation of the reversed words.

Mistake: Not trimming the input string, which can leave leading or trailing spaces.

Solution: Always use str.trim() to clean up the string before processing.

Mistake: Using incorrect split regex for multiple spaces.

Solution: Use split("\s+") to ensure all whitespace variations are handled.