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How To Check Whether a Number is Strontio Number or Not in Java?
A number is said to be a Strontio number, if we multiply 2 with a four-digit number then in the resultant number the tens place and hundreds place digits are the same.
In simple terms, Strontio numbers are basically four-digit numbers. When we multiply 2 with it, it results in a number whose tens place and hundred places are exactly the same.
Some examples of Strontio numbers are- 1111, 2222, 3333, 4444, 5555, 6666, 7777, 8888, 9999, 1001 ... etc.
In this article, we will see how to check if a number is a strontio number by using Java programming language.
To show you some instances
Instance-1
Input number is 1111.
Let’s check it by using the logic of Strontio number.
Multiply 2 with the given number= 1111 * 2 = 2222.
As we notice here both the hundreds place and tens place are same in resultant number.
Hence, 1111 is a Strontio number.
Instance-2
Input number is 7777.
Let’s check it by using the logic of Strontio number.
Multiply 2 with the given number= 7777 * 2 = 15554.
As we notice here both the hundreds place and tens place are same in resultant number.
Hence, 7777 is a Strontio number.
Instance-3
Input number is 1234.
Let’s check it by using the logic of Strontio number.
Multiply 2 with the given number= 1234 * 2 = 2468.
As we notice here both the hundreds place and tens place are not same in resultant number.
Hence, 1234 is not a Strontio number.
Algorithm
Step-1 - Get the four-digit input number either by static input or by user input.
Step-2 - Multiply the input number with 2 and remove all digits from the resultant number except hundreds place and tens place.
Step-3 - Now we have a two-digit number, so we check whether both digits of that number are the same or not.
Step-4 - If both the digits are same, then the input number is called as Strontio number else not.
Multiple Approaches
We have provided the solution in different approaches.
By Using Static Input Value
By Using User Input Value
By User Defined Method
Let’s see the program along with its output one by one.
Approach-1: By Using Static Input Value
In this approach, we declare a variable with a static input value and then by using the algorithm we can check whether the number is a Strontio number or not.
Example
import java.util.*; public class Main { public static void main(String args[]) { //declare a variable and store a number to it by static input method int inputNumber=9999; //declare a variable to store the input value temporarily int temp=inputNumber; //remove all the digits excluding hundreds and tens place digit inputNumber=(inputNumber*2%1000)/10; //Now compare hundreds place value with tens place value if(inputNumber%10==inputNumber/10) //if true System.out.println(temp+ " is a strontio number."); else //if false System.out.println(temp+ " is not a strontio number."); } }
Output
9999 is a strontio number.
Approach-2: By Using User Input Value
In this approach, we take a four-digit number as user input and then by using the algorithm we can check whether the number is a Strontio number or not.
Example
import java.util.*; public class Main { public static void main(String args[]) { //create object of Scanner Class Scanner sc=new Scanner(System.in); //Ask the user to enter a four digit number System.out.print("Enter a four digit number: "); //Declare a variable and store the collected number int inputNumber=sc.nextInt(); //declare a variable to store the input value temporarily int temp=inputNumber; //remove all the digits excluding hundreds and tens place digit inputNumber=(inputNumber*2%1000)/10; //Now compare hundreds place value with tens place value if(inputNumber%10==inputNumber/10) //if true System.out.println(temp+ " is a strontio number."); else //if false System.out.println(temp+ " is not a strontio number."); } }
Output
Enter a four digit number: 2222 2222 is a strontio number.
Approach-3: By Using User Defined Method
In this approach, take a four-digit number as static input and pass this number as a parameter in a user defined method, then inside the method by using the algorithm we can check whether the number is a Strontio number or not.
Example
import java.util.*; public class Main { //main method public static void main(String args[]) { //declare a variable and store a number to it by static input method int inputNumber=3333; //call the user-defined method to check the strontio number if(checkStrontio(inputNumber)) //print if condition true System.out.println(inputNumber+ " is a strontio number."); else //print if condition false System.out.println(inputNumber+ " is not a strontio number."); } //user-defined method to check the strontio number static boolean checkStrontio(int n) { //declare a variable to store the input value temporarily int temp=n; //remove all the digits excluding hundreds and tens place digit n=(n*2%1000)/10; //Now compare hundreds place value with tens place value if(n%10==n/10) //if true return true; else //if false return false; } }
Output
3333 is a strontio number.
In this article, we explored how to check a number whether it is a Strontio number or not in Java by using different approaches.