Java: Extract the first digit from an integer

Last update on May 14 2025 13:03:03 (UTC/GMT +8 hours)

Extract First Digit of Integer

Write a Java method for extracting the first digit from a positive or negative integer.

Pictorial Presentation:

Sample data:
(1234) ->1
(-2345) ->2

Sample Solution:

Java Code:

import java.util.Scanner;
public class Main { 
 public static void main(String[] args)
    {
        Scanner in = new Scanner(System.in);
        System.out.print("Input an integer(positive/negative):");
        int n = in.nextInt();
        System.out.print("Extract the first digit from the said integer:\n");
        System.out.print(test(n));
        }

public static int test(int n){
       int fact_num = 10;
       while(n / fact_num != 0){
        fact_num *= 10;
    }
    return Math.abs(n / (fact_num/10));
  }
}

Sample Output:

Input an integer(positive/negative): 1234
Extract the first digit from the said integer:
1

Flowchart :

For more Practice: Solve these Related Problems:

• Write a Java program to extract the first digit of an integer using logarithmic operations.
• Write a Java program to extract the first digit of an integer without converting it to a string.
• Write a Java program to extract the first digit and then remove it from the given integer.
• Write a Java program to extract the first non-zero digit of an integer that may have leading zeros.

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