Java Guava | gcd(int a, int b) method of IntMath Class

The method gcd(int a, int b) of Guava’s IntMath class returns the greatest common divisor of a, b.

Syntax :

public static int gcd(int a, int b)

Where a and b are integers.

Return Value : Greatest common divisor of integers a and b.

Exceptions : The method gcd(int a, int b) throws IllegalArgumentException if a < 0 or b < 0.

Example 1 :

// Java code to show implementation of
// gcd(int a, int b) method of Guava's
// IntMath class
import java.math.RoundingMode;
import com.google.common.math.IntMath;

class GFG {

    // Driver code
    public static void main(String args[])
    {
        int a1 = 64;
        int b1 = 36;

        // Using gcd(int a, int b) method
        // of Guava's IntMath class
        int ans1 = IntMath.gcd(a1, b1);

        System.out.println("GCD of a1 & b1 is: "
                           + ans1);

        int a2 = 23;
        int b2 = 15;

        // Using gcd(int a, int b) method
        // of Guava's IntMath class
        int ans2 = IntMath.gcd(a2, b2);

        System.out.println("GCD of a2 & b2 is: "
                           + ans2);
    }
}

Output:

GCD of a1 & b1 is: 4
GCD of a2 & b2 is: 1

Example 2 :

// Java code to show implementation of
// gcd(int a, int b) method of Guava's
// IntMath class
import java.math.RoundingMode;
import com.google.common.math.IntMath;

class GFG {

    // Driver code
    public static void main(String args[])
    {
        int a1 = -5;
        int b1 = 15;

        try {
            // Using gcd(int a, int b) method
            // of Guava's IntMath class
            // This should throw "IllegalArgumentException"
            // as a1 < 0
            int ans1 = IntMath.gcd(a1, b1);
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

Output:

java.lang.IllegalArgumentException: a (-5) must be >= 0

Note: The method returns 0 if a == 0 && b == 0.

Reference: https://google.github.io/guava/releases/20.0/api/docs/com/google/common/math/IntMath.html#gcd-int-int-