Basic Programs Every Beginner Must Know (LCM, Sum, Factorial)

# beginners# java# python# tutorial

Abishek

These are the most important beginner problems asked in interviews and tests. Let’s understand them...

These are the most important beginner problems asked in interviews and tests.
Let’s understand them with logic + flow + code in 3 languages.

1. Sum of N Numbers

Find the sum from a starting number to an ending number.

Python

output

JAVA

import java.util.Scanner;

public class SumN {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int start = sc.nextInt();
        int end = sc.nextInt();

        int result = 0;

        while (start <= end) {
            result += start;
            start++;
        }

        System.out.println(result);
    }
}

JavaScript

let start = 1;
let end = 10;

let result = 0;

while (start <= end) {
    result += start;
    start++;
}

console.log(result);

2. LCM (Least Common Multiple)

Find the smallest number divisible by both numbers.

Python

output

JAVA

import java.util.Scanner;

public class LCM {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int a = sc.nextInt();
        int b = sc.nextInt();

        int max = (a > b) ? a : b;

        while (true) {
            if (max % a == 0 && max % b == 0) {
                System.out.println(max);
                break;
            }
            max++;
        }
    }
}

JavaScript

let a = 30;
let b = 35;

let max = a > b ? a : b;

while (true) {
    if (max % a === 0 && max % b === 0) {
        console.log(max);
        break;
    }
    max++;
}

3. Factorial

Find factorial of a number
5! = 5 × 4 × 3 × 2 × 1 = 120

Python

output

JAVA

import java.util.Scanner;

public class Factorial {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        int result = 1;

        while (n > 0) {
            result *= n;
            n--;
        }

        System.out.println(result);
    }
}

JavaScript

let n = 5;
let result = 1;

while (n > 0) {
    result *= n;
    n--;
}

console.log(result);