Combination in java

Asked Dec 22 '22 at 08:47

Active Dec 22 '22 at 08:54

Viewed 63 times

I tried to make a combination program but I got wrong result in big numbers, why?

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        
        
        Scanner scanner = new Scanner(System.in);
        
        System.out.print("Enter element number: ");
        int n = scanner.nextInt();
        System.out.print("selection number: ");
        int r = scanner.nextInt();
        
        int minus = n - r;
        long nFactorial = 1;
        long rFactorial = 1;
        long minusFactorial = 1;
        
        for(int i = 1; i <= n; i++) {
            nFactorial = nFactorial * i;
        }       
        for(int i = 1; i <= r; i++) {
            rFactorial = rFactorial * i;
        }
        for(int i = 1; i <= minus; i++) {
            minusFactorial = minusFactorial * i;
        }
        long comb = nFactorial / (rFactorial * minusFactorial);
        System.out.println("C(" + n + "," + r + ") combination: " + comb);
    }
}

n number: 50

r number: 5

The wrong result: 0

Could you help me?

edited Dec 22 '22 at 08:51

Federico klez Culloca

26,308
17
56
95

asked Dec 22 '22 at 08:47

TheAloneWolf

Integer division http://stackoverflow.com/questions/4685450/why-is-the-result-of-1-3-0 – Scary Wombat Dec 22 '22 at 08:49
You also have a "long" overflow. – Tom Dec 22 '22 at 08:55
Take a look at `BigInteger` – Valerij Dobler Dec 22 '22 at 09:03
I solved with another way. Thanks for everyone! – TheAloneWolf Dec 24 '22 at 11:37

Combination in java

0 Answers0