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Java Method Exercises: Extract the first digit from an integer

Java Method: Exercise-20 with Solution

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

Pictorial Presentation:

Java Method Exercises: Extract the first digit from an integer

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 :

Flowchart: Extract the first digit from an integer

Java Code Editor:

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Previous Java Exercise: Accept three integers and return the middle one.
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Java: Tips of the Day

Prefer primitive classes

Wrapper classes are often slower than primitive classes. While Primitive class only has values, the wrapper class stores information about the entire class. Since the classes often deal with object values, comparing them with primitive classes does not give the desired results.

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