Java.math.BigDecimal.scale() Method

Description

The java.math.BigDecimal.scale() returns the scale of this BigDecimal. If zero or positive, the scale is the number of digits to the right of the decimal point.

If negative, the unscaled value of the number is multiplied by ten to the power of the negation of the scale. For example, a scale of -3 means the unscaled value is multiplied by 1000.

Declaration

Following is the declaration for java.math.BigDecimal.scale() method.

public int scale()
      

Parameters

NA

Return Value

This method returns the scale of this BigDecimal object.

Example

The following example shows the usage of math.BigDecimal.scale() method.

import java.math.*;

public class BigDecimalDemo {

    public static void main(String[] args) {

        // create 2 BigDecimal Objects
        BigDecimal bg1, bg2,bg3,bg4;
        //scale>=0,scale表示小數點後面的位數
        bg1 = new BigDecimal("123.0");
        bg2 = new BigDecimal("-1.123");
        bg3 = new BigDecimal("12345");
        bg4 = bg3.setScale(-2,BigDecimal.ROUND_HALF_UP);
        //scale<0,scale表示小數點後面的位數
// If negative, the unscaled value of the number is multiplied by ten to 
// the power of the negation of the scale. For example, a scale of -3 means the 
// unscaled value is multiplied by 1000.

        // create two int objects
        int i1,i2,i3,i4;

        // assign the result of scale on bg1, bg2 to i1,i2
        i1 = bg1.scale();
        i2 = bg2.scale();
        i3 = bg3.scale();
        i4 = bg4.scale();


        String str1 = "The scale of " + bg1 + " is " + i1;
        String str2 = "The scale of " + bg2 + " is " + i2;
        String str3 = "The scale of " + bg3 + " is " + i3;
        String str4 = "The scale of " + bg4.toString() + " is " + i4;


        // print the values of i1,i2;
        System.out.println( str1 );
        System.out.println( str2 );
        System.out.println( str3 );
        System.out.println( str4 );
    }
}
//result
The scale of 123.0 is 1
The scale of -1.123 is 3
The scale of 12345 is 0
The scale of 1.23E+4 is -2
           

參考：https://www.tutorialspoint.com/java/math/bigdecimal_scale.htm