Java常用类库之Math_java类库math

Math

System.out.println(Math.abs(-100));
//100
System.out.println(Math.min(100, 200));
//100
System.out.println(Math.max(100, 200));
//200

//四舍五入
System.out.println(Math.round(1.5));
//2
System.out.println(Math.round(-1.5));
//-1

//返回最接近的整数（double型）
System.out.println(Math.rint(1.5));
//2.0 
System.out.println(Math.rint(-1.5));
//-2.0

//向下取整
System.out.println(Math.floor(3.5));
//3
System.out.println(Math.floor(-3.5));
//-4

//向上取整
System.out.println(Math.ceil(3.5));
//4
System.out.println(Math.ceil(-3.5));
//-3

//int或long型数值相加
System.out.println(Math.addExact(2, 8));
//10
System.out.println(Math.addExact(2147483647, 3));
//溢出int或long会抛出异常：Exception in thread "main" java.lang.ArithmeticException: integer overflow

//返回值递减1，溢出抛异常
System.out.println(Math.decrementExact(8));
//7
System.out.println(Math.incrementExact(8));
//9

//exp()
System.out.println(Math.exp(1));
//2.718281828459045

//除法，向下取整
System.out.println(Math.floorDiv(8,3));
//2
//返回余数
System.out.println(Math.floorMod(8,3));
//2

//幂
System.out.println(Math.pow(8,2));
//64

//[0,1)的double随机数
System.out.println(Math.random());

//数学常数
System.out.println(Math.PI);
//3.141592653589793
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