Java Number Programs (ISC Classes 11 / 12)
A Smith number is a composite number, whose sum of the digits is equal to the sum of its prime factors. For example:
4, 22, 27, 58, 85, 94, 121 ………. are Smith numbers.
Write a program in Java to enter a number and check whether it is a Smith number or not.
Sample Input: 666
Sum of the digits: 6 + 6 + 6 = 18
Prime factors are: 2, 3, 3, 37
Sum of the digits of the prime factors: 2 + 3 + 3 + (3 + 7) = 18
Thus, 666 is a Smith Number.
Java
Java Iterative Stmts
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Answer
import java.util.Scanner;
public class KboatSmithNumber
{
public static void main(String args[]) {
Scanner in = new Scanner(System.in);
System.out.print("Enter number: ");
int n = in.nextInt();
if (n <= 0) {
System.out.println(n + " is not a Smith Number.");
return;
}
boolean isComposite = false;
for (int i = 2; i < n; i++) {
if (n % i == 0) {
isComposite = true;
break;
}
}
if (isComposite && n != 1) {
int sumDigits = 0;
int t = n;
while (t != 0) {
int d = t % 10;
sumDigits += d;
t /= 10;
}
int sumPrimeDigits = 0;
t = n;
for(int i = 2; i < t; i++) {
while(t % i == 0) {
t /= i;
int temp = i;
while (temp != 0) {
int d = temp % 10;
sumPrimeDigits += d;
temp /= 10;
}
}
}
if(t > 2) {
while (t != 0) {
int d = t % 10;
sumPrimeDigits += d;
t /= 10;
}
}
if (sumPrimeDigits == sumDigits)
System.out.println(n + " is a Smith Number.");
else
System.out.println(n + " is not a Smith Number.");
}
else {
System.out.println(n + " is not a Smith Number.");
}
}
}
Output
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