Guava IntMath类
简介 : IntMath 是用来对整数值进行数学运算的。基本的独立数学函数根据所涉及的主要数字类型被分为IntMath、LongMath、DoubleMath和BigIntegerMath类。这些类具有平行结构，但每个类只支持相关的函数子集。
声明 : com.google.common.math.IntMath类的声明是。
@GwtCompatible(emulated = true)public final class IntMath extends Object
下表显示了Guava的IntMath类所提供的一些方法。
异常情况:
log2 : 如果x<=0，则出现IllegalArgumentExceptionlog10 : 如果x<=0，则出现IllegalArgumentExceptionpow : 如果k<0，则出现IllegalArgumentException。sqrt : 如果x<0，则出现IllegalArgumentExceptiondivide : 如果q == 0，或者mode == UNNECESSARY，并且a不是b的整数倍，则出现ArithmeticException。mod : 如果m<=0，则出现算术异常gcd : 如果a<0或b<0，则出现IllegalArgumentException。checkedAdd : 如果a+b在有符号int算术中溢出，则出现ArithmeticExceptioncheckedSubtract : 如果a-b在有符号整数运算中溢出，则会出现ArithmeticExceptioncheckedMultiply : 如果a * b在有符号int算术中溢出，则出现ArithmeticExceptioncheckedPow : 如果b在有符号的int算术中溢出到第k次幂，则出现ArithmeticExceptionfactorial : 如果n<0，则出现IllegalArgumentExceptionbinomial : 如果n<0，k n，则出现IllegalArgumentException。Guava的IntMath类提供的其他一些方法有:
例1 :
// Java code to show implementation of// IntMath Class of Guavaimport java.math.RoundingMode;import com.google.common.math.IntMath; class GFG { // Driver code public static void main(String args[]) { // Creating an object of GFG class GFG obj = new GFG(); // Function calling obj.examples(); } private void examples() { try { // exception will be thrown as 80 is not // completely divisible by 3 // thus rounding is required, and // RoundingMode is set as UNNESSARY System.out.println(IntMath.divide(80, 3, RoundingMode.UNNECESSARY)); } catch (ArithmeticException ex) { System.out.println("Error Message is : " + ex.getMessage()); } }}
输出:
Error Message is : mode was UNNECESSARY, but rounding was necessary
例2 :
// Java code to show implementation of// IntMath Class of Guavaimport java.math.RoundingMode;import com.google.common.math.IntMath; class GFG { // Driver code public static void main(String args[]) { // Creating an object of GFG class GFG obj = new GFG(); // Function calling obj.examples(); } private void examples() { // As 120 is divisible by 4, so // no exception is thrown System.out.println(IntMath.divide(120, 4, RoundingMode.UNNECESSARY)); // To compute GCD of two integers System.out.println("GCD is : " + IntMath.gcd(70, 14)); // To compute log to base 10 System.out.println("Log10 is : " + IntMath.log10(1000, RoundingMode.HALF_EVEN)); // To compute remainder System.out.println("modulus is : " + IntMath.mod(125, 5)); // To compute factorial System.out.println("factorial is : " + IntMath.factorial(7)); // To compute log to base 2 System.out.println("Log2 is : " + IntMath.log2(8, RoundingMode.HALF_EVEN)); // To compute square root System.out.println("sqrt is : " + IntMath.sqrt(IntMath.pow(12, 2), RoundingMode.HALF_EVEN)); }}
输出:
30GCD is : 14Log10 is : 3modulus is : 0factorial is : 5040Log2 is : 3sqrt is : 12
参考资料 : Google Guava
