to check wheather a number is or odd or not

Scanner scan=new Scanner(System.in);
       int n=scan.nextInt();
       if(n%2==0){
           System.out.println("Even number");
       }else{
           System.out.println("Odd number");
       }
       
===============================================
input will be some marks and output will be grades

if my marks are between 90 to 100 -> A grade
                        80 to 100 -> B grade
                        70 to 100 -> C grade
                        60 to 100 -> d graded
                        59 and below -> Sorry you are failed

import java.util.*;
class HelloWorld {
    public static void main(String[] args) {
       Scanner scan=new Scanner(System.in);
       int marks=scan.nextInt();
       if(marks<=100 && marks>=90){
           System.out.println("A grade");
       }
       else if(marks>=80 && marks<=89){
           System.out.println("B grade");
       }
       else if(marks>=70 && marks<=79){
           System.out.println("C grade");
       }
       else if(marks>=60 && marks<=69){
           System.out.println("D grade");
       }else{
          System.out.println("Sorry you are failed"); 
       }
    }
}
========================================================

if my input n
I want to print numbers from 1 to n
in the same line with a  space

import java.util.*;
class HelloWorld {
    public static void main(String[] args) {
       Scanner scan=new Scanner(System.in);
       int n=scan.nextInt();
       for(int i=1;i<=n;i++){
           System.out.print(i+" ");
       }
       //initialization
       //condition check
       //statements 
       //incr/decr
    }
}
====================================================
import java.util.*;
class HelloWorld {
    public static void main(String[] args) {
       Scanner scan=new Scanner(System.in);
       int n=scan.nextInt();
       int sum=0;
       for(int i=1;i<=n;i++){
           if(i%2==1)
           sum=sum+i;
       }
       System.out.println(sum);
       //initialization
       //condition check
       //statements 
       //incr/decr
    }
}
===============================================
Armstring number means cunbes of digits equal to sum
n=153
153 = 1^3+5^3+3^3
Math.pow(1,3)
=============================================