Guava - IntMath Class

IntMath provides utility methods on int.
Following is the declaration for com.google.common.math.IntMath class −
@GwtCompatible(emulated = true)
public final class IntMath
   extends Object
static int binomial(int n, int k)
Returns n choose k, also known as the binomial coefficient of n and k, or Integer.MAX_VALUE if the result does not fit in an int.
static int checkedAdd(int a, int b)
Returns the sum of a and b, provided it does not overflow.
static int checkedMultiply(int a, int b)
Returns the product of a and b, provided it does not overflow.
static int checkedPow(int b, int k)
Returns the b to the kth power, provided it does not overflow.
static int checkedSubtract(int a, int b)
Returns the difference of a and b, provided it does not overflow.
static int divide(int p, int q, RoundingMode mode)
Returns the result of dividing p by q, rounding using the specified RoundingMode.
static int factorial(int n)
Returns n!, that is, the product of the first n positive integers, 1 if n == 0, or Integer.MAX_VALUE if the result does not fit in a int.
static int gcd(int a, int b)
Returns the greatest common divisor of a, b.
static boolean isPowerOfTwo(int x)
Returns true if x represents a power of two.
static int log10(int x, RoundingMode mode)
Returns the base-10 logarithm of x, rounded according to the specified rounding mode.
static int log2(int x, RoundingMode mode)
Returns the base-2 logarithm of x, rounded according to the specified rounding mode.
static int mean(int x, int y)
Returns the arithmetic mean of x and y, rounded towards negative infinity.
static int mod(int x, int m)
Returns x mod m, a non-negative value less than m.
static int pow(int b, int k)
Returns b to the kth power.
static int sqrt(int x, RoundingMode mode)
Returns the square root of x, rounded with the specified rounding mode.
This class inherits methods from the following class −
java.lang.Object
Create the following java program using any editor of your choice in say C:/> Guava.
import java.math.RoundingMode;
import com.google.common.math.IntMath;

public class GuavaTester {

   public static void main(String args[]) {
      GuavaTester tester = new GuavaTester();
      tester.testIntMath();
   }

   private void testIntMath() {
      try {
         System.out.println(IntMath.checkedAdd(Integer.MAX_VALUE, Integer.MAX_VALUE));
         
      } catch(ArithmeticException e) {
         System.out.println("Error: " + e.getMessage());
      }

      System.out.println(IntMath.divide(100, 5, RoundingMode.UNNECESSARY));
      try {
         //exception will be thrown as 100 is not completely divisible by 3
         // thus rounding is required, and RoundingMode is set as UNNESSARY
         System.out.println(IntMath.divide(100, 3, RoundingMode.UNNECESSARY));
         
      } catch(ArithmeticException e) {
         System.out.println("Error: " + e.getMessage());
      }

      System.out.println("Log2(2): " + IntMath.log2(2, RoundingMode.HALF_EVEN));

      System.out.println("Log10(10): " + IntMath.log10(10, RoundingMode.HALF_EVEN));

      System.out.println("sqrt(100): " + IntMath.sqrt(IntMath.pow(10,2), RoundingMode.HALF_EVEN));

      System.out.println("gcd(100,50): " + IntMath.gcd(100,50));

      System.out.println("modulus(100,50): " + IntMath.mod(100,50));

      System.out.println("factorial(5): " + IntMath.factorial(5));
   }
}
Compile the class using javac compiler as follows −
C:\Guava>javac GuavaTester.java

Now run the GuavaTester to see the result.
C:\Guava>java GuavaTester

See the result.
Error: overflow
20
Error: mode was UNNECESSARY, but rounding was necessary
Log2(2): 1
Log10(10): 1
sqrt(100): 10
gcd(100,50): 50
modulus(100,50): 0
factorial(5): 120

 Print
 Add Notes
 Bookmark this page