Java java.math.MathContext用法及代碼示例

// Java Program to illustrate java.math.Context class 
  
// Importing all classes from 
// java.math package 
import java.math.*; 
  
// Main class 
class GFG { 
  
    // Main driver method 
    public static void main(String args[]) 
    { 
  
        // Custom input number 'N' over which 
        // class operation are performed 
        // N = 246.8 
  
        // erforming the rounding of operations 
  
        // Rounding  off is carried out across 
        // 4 digits 
        // N = 246.8 
        // It has 4 digits only so 
        // the output is same as input 
  
        // Case 1 
        // Across all digits of the input N = 4 
        System.out.println(new BigDecimal( 
            "246.8", 
            new MathContext(4, RoundingMode.HALF_UP))); 
  
        // Case 2 
        // Across 'N/2' of the input 'N' 
        // Here, acrossings 2 digits as input N has 4 digits 
  
        // Rounding HALF_UP 
        System.out.println(new BigDecimal( 
            "246.8", 
            new MathContext(2, RoundingMode.HALF_UP))); 
  
        // Rounding HALF_DOWN 
        System.out.println(new BigDecimal( 
            "246.8", 
            new MathContext(2, RoundingMode.CEILING))); 
  
        // Case 3 
        // Across '1' digit of the input 'N' 
        // Here, acrossings 2 digits of 4 digits of input N 
  
        // Rounding HALF_UP 
        System.out.println(new BigDecimal( 
            "246.8", 
            new MathContext(1, RoundingMode.HALF_UP))); 
  
        // Rounding HALF_DOWN 
        System.out.println(new BigDecimal( 
            "246.8", 
            new MathContext(1, RoundingMode.CEILING))); 
    } 
}