BigDecimal calculation
In this chapter you will learn:
- What methods to use to do calculation on BigDecimal
- How to get absolute value from BigDecimal
- How to add two BigDecimal value together
- Calculating Euler's number e with BigDecimal
- Multiply one BigDecimal to another BigDecimal
Methods to do calculation
BigDecimal abs()/*from ja v a 2 s. co m*/
BigDecimal abs(MathContext mc)
BigDecimal add(BigDecimal augend)
BigDecimal add(BigDecimal augend, MathContext mc)
BigDecimal divide(BigDecimal divisor)
BigDecimal divide(BigDecimal divisor, int roundingMode)
BigDecimal divide(BigDecimal divisor, int scale, int roundingMode)
BigDecimal divide(BigDecimal divisor, int scale, RoundingMode roundingMode)
BigDecimal divide(BigDecimal divisor, MathContext mc)
BigDecimal divide(BigDecimal divisor, RoundingMode roundingMode)
BigDecimal[]divideAndRemainder(BigDecimal divisor)
BigDecimal[]divideAndRemainder(BigDecimal divisor, MathContext mc)
BigDecimal divideToIntegralValue(BigDecimal divisor)
BigDecimal divideToIntegralValue(BigDecimal divisor, MathContext mc)
BigDecimal max(BigDecimal val)
BigDecimal min(BigDecimal val)
BigDecimal multiply(BigDecimal multiplicand)
BigDecimal multiply(BigDecimal multiplicand, MathContext mc)
BigDecimal negate()
BigDecimal negate(MathContext mc)
BigDecimal plus()
BigDecimal plus(MathContext mc)
BigDecimal pow(int n)
BigDecimal pow(int n, MathContext mc)
BigDecimal remainder(BigDecimal divisor)
BigDecimal remainder(BigDecimal divisor, MathContext mc)
BigDecimal round(MathContext mc)
BigDecimal scaleByPowerOfTen(int n)
BigDecimal subtract(BigDecimal subtrahend)
BigDecimal subtract(BigDecimal subtrahend, MathContext mc)
Absolute value
The following code calls abs() method to return
the absolute value from a BigDecimal.
import java.math.BigDecimal;
/* jav a 2 s . c om*/
public class Main {
public static void main(String[] args) {
BigDecimal first = new BigDecimal(-1f);
System.out.println(first);
System.out.println(first.abs());
}
}
The output:
Add two BigDecimal value together
We can use add() method to add one BigDecimal value to another.
import java.math.BigDecimal;
//from j av a 2s . co m
public class Main {
public static void main(String[] args) {
BigDecimal first = new BigDecimal(-1f);
BigDecimal second = new BigDecimal(10f);
BigDecimal result = first.add(second);
System.out.println(result);
}
}
The output:
Calculating Euler's number e with BigDecimal
import java.math.BigDecimal;
import java.math.MathContext;
import java.math.RoundingMode;
//from j a v a2s . co m
public class Main {
final static int LASTITER = 17;
public static void main(String[] args) {
MathContext mc = new MathContext(100, RoundingMode.HALF_UP);
BigDecimal result = BigDecimal.ZERO;
for (int i = 0; i <= LASTITER; i++) {
BigDecimal factorial = factorial(new BigDecimal(i));
BigDecimal res = BigDecimal.ONE.divide(factorial, mc);
result = result.add(res);
}
System.out.println(result);
}
public static BigDecimal factorial(BigDecimal n) {
if (n.equals(BigDecimal.ZERO))
return BigDecimal.ONE;
else
return n.multiply(factorial(n.subtract(BigDecimal.ONE)));
}
}
The code above generates the following result.
Multiply one BigDecimal to another BigDecimal
import java.math.BigDecimal;
// ja v a 2 s . co m
public class Main {
public static void main(String[] argv) throws Exception {
BigDecimal bd1 = new BigDecimal("123456789.0123456890");
// Create via a long
BigDecimal bd2 = BigDecimal.valueOf(123L);
bd1 = bd1.multiply(bd2);
System.out.println(bd1);
}
}
Output:
Next chapter...
What you will learn in the next chapter:
- How to convert BigDecimal to primitive data types
- How to convert to float type value
- Convert double and long to BigDecimal
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