First Non-Repeating Character in Java: Explanation & Practice

Problem summary

Write a program that finds the first character that appears only once in a string.

Starter code

public class Main {
    public static void main(String[] args) {
        String text = "programming"; // Test case 1
        
        // Find first non-repeating character
        // Print: First unique: <char> OR No unique character
    }
}

Expected output and test cases

• p is first unique

  First unique: p

• First unique in aabbc

  First unique: a

• All repeat

  No unique character

Hints

1. Count occurrence of each character first
2. Then find first with count 1
3. Can use array of size 26 for counts

Related Strings exercises

• Practice Count Vowels in Java
• Practice Count Words in Java
• Practice Anagram Check in Java

Practice all Strings exercises · Run this idea in the Java compiler