Where we learn technology

Day: 6 January 2019

How to find Armstrong Number

How to find Armstrong Number

Learn:
1. check the given number is Armstrong or not.
2. write different test cases for Armstrong Number

Code:

package Questions;
public class ArmstrongNumber {
//153
//1*1*1 = 1
//5*5*5 = 125
//3*3*3 = 27
//1+125+27 = 153
//407 == 4*4*4 + 0 + 7*7*7 = 407
//0
//1 == 1*1*1 = 1
//370, 371
public static void isArmstrongNumber(int num){
//153 ==  1*1*1    5*5*5      3*3*3
System.out.println(“given number is “+ num );
int cube = 0;
int r;
int t;
t=num;
while(num>0){
r = num%10; 
num = num/10;
cube = cube+(r*r*r);
}
if(t==cube){
System.out.println(“this is an armstrong number”);
}else{
System.out.println(“this is not an armstrong number”);
}
}
public static void main(String[] args) {
isArmstrongNumber(153);
isArmstrongNumber(370);
isArmstrongNumber(0);
isArmstrongNumber(1);
isArmstrongNumber(455);
}
}

How to check Palindrome Number

How to check Palindrome Number


Learn:
1. check the given number is Palindrome or not.
2. write different test cases



Code:


package Questions;
public class PalindromeNumber {
//151 454 34543 161 78987  
//teet
public static void isPalindromeNumber(int num){
System.out.println(“Given Number is :” + num);
int r=0;
int sum=0;
int t;
t=num;
while(num>0){
r = num%10; //get the remainder
sum = (sum*10)+r;
num=num/10;
}
if(t==sum){
System.out.println(“palindrome number”);
}else{
System.out.println(“not palindrome number”);
}
}
public static void main(String[] args) {
isPalindromeNumber(151);
isPalindromeNumber(152);
isPalindromeNumber(78987);
isPalindromeNumber(1110);
isPalindromeNumber(0);
}
}

How to find Prime Number

How to find Prime Number in Java

Learn:
1. check the given number is prime or not.
2. print all the prime numbers upto a given a number
3. write different test cases

Code:

package Questions;
public class PrimeNumber {
//2 is the lowest prime number
//3
//num = 20
public static boolean isPrimeNumber(int num){
//edge/corner cases:
if(num<=1){
return false;
}
for(int i=2; i<num; i++){
if(num % i == 0){
return false;
}
}
return true;
}
public static void getPrimeNumbers(int num){
for(int i=2; i<=num; i++){
if(isPrimeNumber(i))
System.out.print(i + ” “);
}
}
public static void main(String[] args) {
System.out.println(“2 is prime number: “+ isPrimeNumber(2));
System.out.println(“3 is prime number: “+ isPrimeNumber(2));
System.out.println(“10 is prime number: “+ isPrimeNumber(10));
System.out.println(“17 is prime number: “+ isPrimeNumber(17));
System.out.println(“0 is prime number: “+ isPrimeNumber(0));
System.out.println(“1 is prime number: “+ isPrimeNumber(0));
System.out.println(“-3 is prime number: “+ isPrimeNumber(-3));
getPrimeNumbers(7);
getPrimeNumbers(13);
getPrimeNumbers(20);
}
}