Remove-Last-Digit Number Pattern in Java

What You’ll Learn

This pattern prints a number, then repeatedly removes the last digit with integer division by 10. Starting from 86523: 86523, 8652, 865, 86, 8. A single while loop handles it — no nested loops needed. This tutorial covers the loop logic, live preview, worked Java examples, edge cases, and O(d) complexity.

📝 Problem & Approach

Given starting number num = 86523, print each value as you remove the last digit until the number becomes zero.

// num = 86523 (conceptual output)
// 86523
// 8652
// 865
// 86
// 8

Inputs & Outputs

Minimal workflow

while num != 0:
    print num
    num = num / 10

Approach comparison

🔮 Live Preview

Enter a starting number and see each digit-removal line in the browser.

Press "Draw pattern".

Examples Gallery

Three complete Java programs — fixed num = 86523, Scanner input, and a string-substring variant. Click View Output to reveal sample console results.

public class RemoveLastDigitPattern {
    public static void main(String[] args) {
        int num = 86523;

        while (num != 0) {
            System.out.println(num);
            num = num / 10;
        }
    }
}

86523
8652
865
86
8

import java.util.Scanner;

public class RemoveLastDigitInput {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter a number: ");
        int num = sc.nextInt();

        while (num != 0) {
            System.out.println(num);
            num = num / 10;
        }

        sc.close();
    }
}

Enter a number: 86523
86523
8652
865
86
8

public class RemoveLastDigitString {
    public static void main(String[] args) {
        int num = 86523;
        String s = String.valueOf(num);

        for (int len = s.length(); len >= 1; len--) {
            System.out.println(s.substring(0, len));
        }
    }
}

86523
8652
865
86
8

🔎 Worked Walkthrough — num = 86523

Trace each loop iteration: print, then divide by 10.

Zero is never printed because the loop condition is checked before the next iteration.

🎯 Practice Problems

Try these variations to lock in the pattern.

Notes

⏱️ Time and Space Complexity

💡 Best Practices