LongMath provides utility methods on long.
Class Declaration
Following is the declaration for com.google.common.math.LongMath class −
@GwtCompatible(emulated = true) public final class LongMath extends Object
Methods
| Sr.No | Method & Description |
|---|---|
| 1 | static long binomial(int n, int k)Returns n choose k, also known as the binomial coefficient of n and k, or Long.MAX_VALUE if the result does not fit in a long. |
| 2 | static long checkedAdd(long a, long b)Returns the sum of a and b, provided it does not overflow. |
| 3 | static long checkedMultiply(long a, long b)Returns the product of a and b, provided it does not overflow. |
| 4 | static long checkedPow(long b, int k)Returns the b to the kth power, provided it does not overflow. |
| 5 | static long checkedSubtract(long a, long b)Returns the difference of a and b, provided it does not overflow. |
| 6 | static long divide(long p, long q, RoundingMode mode)Returns the result of dividing p by q, rounding using the specified RoundingMode. |
| 7 | static long factorial(int n)Returns n!, that is, the product of the first n positive integers, 1 if n == 0, or Long.MAX_VALUE if the result does not fit in a long. |
| 8 | static long gcd(long a, long b)Returns the greatest common divisor of a, b. |
| 9 | static boolean isPowerOfTwo(long x)Returns true if x represents a power of two. |
| 10 | static int log10(long x, RoundingMode mode)Returns the base-10 logarithm of x, rounded according to the specified rounding mode. |
| 11 | static int log2(long x, RoundingMode mode)Returns the base-2 logarithm of x, rounded according to the specified rounding mode. |
| 12 | static long mean(long x, long y)Returns the arithmetic mean of x and y, rounded toward negative infinity. |
| 13 | static int mod(long x, int m)Returns x mod m, a non-negative value less than m. |
| 14 | static long mod(long x, long m)Returns x mod m, a non-negative value less than m. |
| 15 | static long pow(long b, int k)Returns b to the kth power. |
| 16 | static long sqrt(long x, RoundingMode mode)Returns the square root of x, rounded with the specified rounding mode. |
Methods Inherited
This class inherits methods from the following class −
- java.lang.Object
Example of LongMath Class
Create the following java program using any editor of your choice in say C:/> Guava.
GuavaTester.java
import java.math.RoundingMode;
import com.google.common.math.LongMath;
public class GuavaTester {
public static void main(String args[]) {
GuavaTester tester = new GuavaTester();
tester.testLongMath();
}
private void testLongMath() {
try {
System.out.println(LongMath.checkedAdd(Long.MAX_VALUE, Long.MAX_VALUE));
} catch(ArithmeticException e) {
System.out.println("Error: " + e.getMessage());
}
System.out.println(LongMath.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(LongMath.divide(100, 3, RoundingMode.UNNECESSARY));
} catch(ArithmeticException e) {
System.out.println("Error: " + e.getMessage());
}
System.out.println("Log2(2): " + LongMath.log2(2, RoundingMode.HALF_EVEN));
System.out.println("Log10(10): " + LongMath.log10(10, RoundingMode.HALF_EVEN));
System.out.println("sqrt(100): " + LongMath.sqrt(LongMath.pow(10,2), RoundingMode.HALF_EVEN));
System.out.println("gcd(100,50): " + LongMath.gcd(100,50));
System.out.println("modulus(100,50): " + LongMath.mod(100,50));
System.out.println("factorial(5): " + LongMath.factorial(5));
}
}
Verify the Result
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
Previous Page:-Click Here
Pingback: ลูกล้อยูรีเทน