How to Check if an Integer is a Multiple of Another Number in Java?

How can I determine if a given integer in Java is a multiple of another integer?

int n = 15; // number to check
int divisor = 5; // divisor
boolean isMultiple = n % divisor == 0; // check if multiple
System.out.println(n + " is a multiple of " + divisor + ": " + isMultiple);

In Java, determining whether an integer is a multiple of another integer can be efficiently achieved using the modulus operator (%). This operator returns the remainder of a division operation. If the result is zero when the first number is divided by the second, it indicates that the first number is a multiple of the second.

public class CheckMultiple {
    public static void main(String[] args) {
        int number = 20;  // number to check
        int divisor = 4;  // divisor
        boolean isMultiple = checkMultiple(number, divisor);
        System.out.println(number + " is a multiple of " + divisor + ": " + isMultiple);
    }

    public static boolean checkMultiple(int num, int div) {
        // Avoid division by zero
        if (div == 0) {
            throw new IllegalArgumentException("Divisor cannot be zero");
        }
        return num % div == 0;
    }
}

Causes

• Incorrect use of the modulus operator.
• Mistaking the order of operands.
• Using primitive data types without checking for overflows.

Solutions

• Utilize the modulus operator correctly to check for remainders appropriately.
• Ensure the divisor is not zero to prevent arithmetic exceptions.
• Implement input validation to handle edge cases like negative numbers or zero.

Mistake: Forgetting to handle division by zero.

Solution: Always check if the divisor is zero before performing modulus operations.

Mistake: Misusing the modulus operator resulting in incorrect results.

Solution: Confirm that the operator is used as intended; check for remainders.