JAVA PROGRAM • LEVEL 07 — STRINGS & TEXT PROCESSING
Count Vowels in a String in Java
Learn count vowels in a string in java with a complete, compiler-ready Java 17 example.
PROBLEM UNDERSTANDING
Input and expected output
No input required
10
COMPLETE JAVA 17 PROGRAM
Complete Java 17 implementation
class Main {
public static void main(String[] args) throws Exception {
String text="Artificial Intelligence".toLowerCase(); int count=0;
for(char ch:text.toCharArray())if("aeiou".indexOf(ch)>=0)count++;
System.out.println(count);
}
}CURRENT STEP
Select Start to walk through the important lines.
SELECTED LINE
No line selected
EXPECTED OUTPUT FOR THE SAMPLE
10
PROGRAM EXPLANATION
Algorithm and explanation
- Initialize the deterministic sample values used for count vowels in a string in java.
- Apply toCharArray() and Vowel test in the order shown by the program.
- Print the final result and compare it with the documented sample output.
This Java 17 example demonstrates toCharArray() and Vowel test through a complete, executable program. The values are intentionally small so students can trace each statement, verify the output, and then modify the example safely in the online compiler.
EFFICIENCY
Time and space complexity
O(n)
O(1)
DEBUGGING CHECKLIST
Common mistakes
Keep the class name Main and the entry method signature public static void main(String[] args) when using the online compiler.
Check the loop boundary and update expression carefully to avoid skipping the final value or creating an infinite loop.
Java is case-sensitive, and every statement that requires a semicolon must end with one.