Math Methods

자바에서 주로 쓰이는 숫자 메소드들에 대해 정리하였습니다.

 

 

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< Introduction >

The Java Math class is part of the java.lang package which is available by default; it contains a variety of methods that can be used to perform numerical calculations in our programs.

Every method in the Math class is static. This means that we can call and use these methods without creating an object of the class.

 

 

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< Calling Static Methods >

There are two main options for calling a static method.

 

1. Our first option is to append the dot operator to the class name followed by the method we want to execute.

: Math.method( )

class Numbers {
  public static void main(String[] args) {
    // Call method using the Class name, the dot operator, the method name, and arguments
    int smallerNumber = Math.min(3, 10);
    System.out.println(smallerNumber); // Prints: 3
  }
}

 

2. Our second option for calling a static method from the Math class is to import the class by adding import static java.lang.Math.*;

import static java.lang.Math.*; // import Math class
 
class Numbers {
  public static void main(String[] args) {
    // Call method by using method name and arguments
    int smallerNumber = min(3, 10);
    System.out.println(smallerNumber); // Prints: 3
  }
}

 

 

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< int abs(int x) >

Returns the absolute value of an int value

 

Example)

System.out.println(Math.abs(5)); // Prints: 5
System.out.println(Math.abs(-5)); // Prints: 5

 

 

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< double abs(double x) >

Returns the absolute value of a double value

 

Example)

System.out.println(Math.abs(5.0)); // Prints: 5.0
System.out.println(Math.abs(-5.0)); // Prints: 5.0

 

 

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< double pow(double base, double exponent) >

Returns the value of the first parameter raised to the power of the second parameter.

 

Example)

double x = Math.pow(5, 3);
System.out.println(x); // Prints: 125.0

 

 

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< double sqrt(double x) >

Returns the positive square root of a double value

 

Example)

double x = Math.sqrt(49); 
System.out.println(x); // Prints: 7.0
double y = Math.sqrt(52); 
System.out.println(y); // Prints: 7.211102550927978

 

 

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< double random() >

Returns a double value greater than or equal to 0.0 and less than 1.0

 

Example)

System.out.println(Math.random()); // 0.8592007008856128
System.out.println(Math.random()); // 0.6120058754881421
System.out.println(Math.random()); // 0.48259656765819403

 

+.  if we wanted an int value in the range of minValue up to and including maxValue

: (Math.random() * (maxValue - minValue + 1)) + minValue

// Random int value between 10 and 20
int d = (int)(Math.random() * 11 ) + 10;

: (int) means type conversion!

Reference: https://kephilab.tistory.com/27

3. Java 자바 - 자동 타입 변환, 강제 타입 변환

 

 

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To see all the methods offered by the Math class, check out the official documentation for the Math class.

Math (Java Platform SE 8 )