Java Number Programs (ICSE Classes 9 / 10)
Write a menu driven program to accept a number from the user and check whether it is a Prime number or an Automorphic number.
(a) Prime number: (A number is said to be prime, if it is only divisible by 1 and itself)
Example: 3,5,7,11
(b) Automorphic number: (Automorphic number is the number which is contained in the last digit(s) of its square.)
Example: 25 is an Automorphic number as its square is 625 and 25 is present as the last two digits.
Java
Java Iterative Stmts
ICSE 2010
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Answer
import java.util.Scanner;
public class KboatPrimeAutomorphic
{
public static void main(String args[]) {
Scanner in = new Scanner(System.in);
System.out.println("1. Prime number");
System.out.println("2. Automorphic number");
System.out.print("Enter your choice: ");
int choice = in.nextInt();
System.out.print("Enter number: ");
int num = in.nextInt();
switch (choice) {
case 1:
int c = 0;
for (int i = 1; i <= num; i++) {
if (num % i == 0) {
c++;
}
}
if (c == 2)
System.out.println(num + " is Prime");
else
System.out.println(num + " is not Prime");
break;
case 2:
int numCopy = num;
int sq = num * num;
int d = 0;
/*
* Count the number of
* digits in num
*/
while(num > 0) {
d++;
num /= 10;
}
/*
* Extract the last d digits
* from square of num
*/
int ld = (int)(sq % Math.pow(10, d));
if (ld == numCopy)
System.out.println(numCopy + " is automorphic");
else
System.out.println(numCopy + " is not automorphic");
break;
default:
System.out.println("Incorrect Choice");
break;
}
}
}
Variable Description Table
Program Explanation
Output
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