Java: Convert 3 digits positive number in given format

Last update on May 13 2025 12:59:56 (UTC/GMT +8 hours)

Convert 3-Digit Numbers to "HHTTT123" Format

Let us use the letter H to mean "hundred", the letter T to mean "ten" and “1, 2, . . . n” to represent the one digit n (<10). Using the given format, write a Java program that converts 3 digits positive numbers. For example, 234 should be output as BBSSS1234 because it has 2 "hundreds", 3 "ten", and 4 ones.

Input:
235
230
Output:
HHTTT12345
HHTTT

Visual Presentation:

Sample Solution:

Java Code:

// Importing Scanner class for user input
import java.util.Scanner;

// Defining a class named "Main"
public class Main {
    
    // Main method, the entry point of the program
    public static void main(String[] args) {
        // Creating a Scanner object for reading user input
        Scanner in = new Scanner(System.in);
        
        // Prompting the user to input a positive number with a maximum of three digits
		System.out.println("Input a positive number(max three digits):");
        
        // Reading an integer, formatting it as a three-digit string, and converting it to a character array
        char[] num = String.format("%03d", in.nextInt()).toCharArray();
        
        // Creating a StringBuilder object to build the result string
        StringBuilder tm = new StringBuilder();
        
        // Appending "H" to the StringBuilder based on the hundreds digit of the input number
        for (int i = 0; i < num[0] - '0'; i++) {
            tm.append("H");
        }
        
        // Appending "T" to the StringBuilder based on the tens digit of the input number
        for (int i = 0; i < num[1] - '0'; i++) {
            tm.append("T");
        }
        
        // Appending numbers from 1 to the units digit to the StringBuilder
        for (int i = 0; i < num[2] - '0'; i++) {
            tm.append(i + 1);
        }
        
        // Printing the result
		System.out.println("Result:");		
        System.out.println(tm.toString());
    }
} 

Sample Output:

Input a positive number(max three digits):
235
Result:
HHTTT12345

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Java program to convert a 3-digit number into a format that spells out hundreds, tens, and ones in words.
• Write a Java program to format a 3-digit number so that the hundreds, tens, and ones are separated by hyphens.
• Write a Java program to convert a 3-digit number into a custom format with leading zeros for tens and ones if necessary.
• Write a Java program to transform a 3-digit number into a string format that prefixes each digit with a corresponding letter code.

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• Java Basic Part-II Programming Exercises Home ↩
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