java基础类库学习（一.3）Math类

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对数学运算的抽象类Math？

Math类提供了复杂的数学运算的计算方法，Math类中所有的方法都是类方法，变量都是类变量

Math不允许创建实例，因此构造器为私有的

Math类源码？

public final class Math {

private Math() {}

public static final double E = 2.7182818284590452354;

public static final double PI = 3.14159265358979323846;

public static double sin(double a) {
    return StrictMath.sin(a); // default impl. delegates to StrictMath
}

public static double cos(double a) {
    return StrictMath.cos(a); // default impl. delegates to StrictMath
}

public static double log(double a) {
    return StrictMath.log(a); // default impl. delegates to StrictMath
}

public static double sqrt(double a) {
    return StrictMath.sqrt(a); // default impl. delegates to StrictMath
                               // Note that hardware sqrt instructions
                               // frequently can be directly used by JITs
                               // and should be much faster than doing
                               // Math.sqrt in software.
}

public static double floor(double a) {
    return StrictMath.floor(a); // default impl. delegates to StrictMath
}

public static double pow(double a, double b) {
    return StrictMath.pow(a, b); // default impl. delegates to StrictMath
}

public static double random() {
    return RandomNumberGeneratorHolder.randomNumberGenerator.nextDouble();
}

}