java-number2

abs() :该方法给出了参数的绝对值，参数可以是int,float,long,double,short,byte

Syntax
double abs(double d)
float abs(float f)
int abs(int i)
long abs(long lng)

public class Test { 

   public static void main(String args[]) {
      Integer a = -8;
      double d = -100;
      float f = -90;

      System.out.println(Math.abs(a));
      System.out.println(Math.abs(d));     
      System.out.println(Math.abs(f));    
   }
}

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ceil():该方法给出大于或等于参数的最小整数

Syntax
double ceil(double d)
double ceil(float f)

public class Test { 

   public static void main(String args[]) {
      double d = -100.675;
      float f = -90;    

      System.out.println(Math.ceil(d));
      System.out.println(Math.ceil(f)); 

      System.out.println(Math.floor(d));
      System.out.println(Math.floor(f)); 
   }
}

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floor() 该方法给出小于或等于参数的最大整数

Syntax
double floor(double d)
double floor(float f)

public class Test { 

   public static void main(String args[]) {
      double d = -100.675;
      float f = -90;

      System.out.println(Math.floor(d));
      System.out.println(Math.floor(f)); 

      System.out.println(Math.ceil(d));
      System.out.println(Math.ceil(f));
   }
}

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rint():返回值最接近参数的整数

Syntax
double rint(double d)

public class Test {

   public static void main(String args[]) {
      double d = 100.675;
      double e = 100.500;
      double f = 100.200;

      System.out.println(Math.rint(d));
      System.out.println(Math.rint(e)); 
      System.out.println(Math.rint(f)); 
   }
}

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round():返回最接近的long或int

Syntax
This method has the following variants −

long round(double d)
int round(float f)

public class Test { 

   public static void main(String args[]) {
      double d = 100.675;
      double e = 100.500;
      float f = 100;
      float g = 90f;

      System.out.println(Math.round(d));
      System.out.println(Math.round(e)); 
      System.out.println(Math.round(f)); 
      System.out.println(Math.round(g)); 
   }
}

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min():给出两个参数的最小值，参数可以是int,float,long,double

Syntax
This method has the following variants −

double min(double arg1, double arg2)
float min(float arg1, float arg2)
int min(int arg1, int arg2)
long min(long arg1, long arg2)

public class Test {

   public static void main(String args[]) {
      System.out.println(Math.min(12.123, 12.456));      
      System.out.println(Math.min(23.12, 23.0));  
   }
}

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max() 给出两个参数最大值，参数可以是int,float,long,double

Syntax
This method has the following variants −

double max(double arg1, double arg2)
float max(float arg1, float arg2)
int max(int arg1, int arg2)
long max(long arg1, long arg2)

public class Test { 

   public static void main(String args[]) {
      System.out.println(Math.max(12.123, 12.456));      
      System.out.println(Math.max(23.12, 23.0));  
   }
}
![](https://images2018.cnblogs.com/blog/1202026/201806/1202026-20180606230843119-1176811323.png)

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pow():返回第一个参数基于第二参数次方的值

public class Test { 

   public static void main(String args[]) {
      double x = 11.635;
      double y = 2.76;

      System.out.printf("The value of e is %.4f%n", Math.E);
      System.out.printf("pow(%.3f, %.3f) is %.3f%n", x, y, Math.pow(x, y));
   }
}

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Math.sqrt() 平方根
Math.sin()
Math.cos()
Math.tan()
....
Math.random() 产生一个0到1的随机数