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Java: Reads an positive integer and count the number of digits

Java Conditional Statement: Exercise-29 with Solution

Write a Java program that reads an positive integer and count the number of digits the number (less than ten billion) has.

Test Data
Input an integer number less than ten billion: 125463

Pictorial Presentation:

Java conditional statement Exercises: Reads an positive integer and count the number of digits

Sample Solution:

Java Code:

import java.util.Scanner;
public class Exercise29 {

   public static void main(String[] args)
    {
        Scanner in = new Scanner(System.in);
        System.out.print("Input an integer number less than ten billion: ");

        if (in.hasNextLong())
        {

            long n = in.nextLong();

            if (n < 0)
            {
                n *= -1;
            }
            if (n >= 10000000000L)
            {
                System.out.println("Number is greater or equals 10,000,000,000!");
            }
            else
            {
                int digits = 1;
                if (n >= 10 && n < 100)
                {
                    digits = 2;
                }
                else if (n >= 100 && n < 1000)
                {
                    digits = 3;
                }
                else if (n >= 1000 && n < 10000)
                {
                    digits = 4;
                }
                else if (n >= 10000 && n < 100000)
                {
                    digits = 5;
                }
                else if (n >= 100000 && n < 1000000)
                {
                    digits = 6;
                }
                else if (n >= 1000000 && n < 10000000)
                {
                    digits = 7;
                }
                else if (n >= 10000000 && n < 100000000)
                {
                    digits = 8;
                }
                else if (n >= 100000000 && n < 1000000000)
                {
                    digits = 9;
                }
                else if (n >= 1000000000 && n < 10000000000L)
                {
                    digits = 10;
                }
                System.out.println("Number of digits in the number: " + digits);
            }
        }
        else
        {
            System.out.println("The number is not an integer");
        }
    }
}

Sample Output:

Input an integer number less than ten billion: 125463                                                         
Number of digits in the number: 6 

Flowchart:

Flowchart: Java Conditional Statement Exercises - Reads an positive integer and count the number of digits

Java Code Editor:

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Previous: Write a Java program that reads a floating-point number. If the number is zero it prints "zero", otherwise, print "positive" or "negative". Add "small" if the absolute value of the number is less than 1, or "large" if it exceeds 1,000,000.
Next: Write a Java program that accepts three numbers and prints "All numbers are equal" if all three numbers are equal, "All numbers are different" if all three numbers are different and "Neither all are equal or different" otherwise.

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Java: Tips of the Day

IsPowerOfTwo

Checks if a value is positive power of two.

To understand how it works let's assume we made a call IsPowerOfTwo(4).

As value is greater than 0, so right side of the && operator will be evaluated.

The result of (~value + 1) is equal to value itself. ~100 + 001 => 011 + 001 => 100. This is equal to value.

The result of (value & value) is value. 100 & 100 => 100.

This will value the expression to true as value is equal to value.

public static boolean isPowerOfTwo(final int value) {
    return value > 0 && ((value & (~value + 1)) == value);
}

Ref: https://bit.ly/3sA5d4I

 





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