[자바] 정확한 실수 표현 BigInteger / BigDecimal

package Basic;

import java.math.BigDecimal;

public class BigDecimalTest {

	public static void main(String[] args) {

		
		double d1= 1.6;
		double d2= 0.1;
		System.out.println("d1 : " + d1);
		System.out.println("d2 : " + d2);
		System.out.println("d1 + d2 : "+ (d1+d2));
		System.out.println("d1 * d2 : "+ (d1*d2));
		
		BigDecimal e1 = new BigDecimal("1.6");
		BigDecimal e2 = new BigDecimal("0.1");
		
		System.out.println("두 실수의 덧셈결과: "+ e1.add(e2));
		System.out.println("두 실수의 곱셈결과: "+ e1.multiply(e2));
	}

}
​

 

최대 정수 표현 : 9223372036854775807
최소 정수 표현 : -9223372036854775808
덧셉 : -8999999999999999999999999
곱셈 : -9999999999999999999999999000000000000000000000000

 

package Basic;

import java.math.BigInteger;

public class BigIntergerTest {

	public static void main(String[] args) {

		System.out.println("최대 정수 표현 : " + Long.MAX_VALUE);
		System.out.println("최소 정수 표현 : " + Long.MIN_VALUE);
		
		BigInteger bigValue1 = new BigInteger("1000000000000000000000000");
		BigInteger bigValue2 = new BigInteger("-9999999999999999999999999");
		
		BigInteger addResult = bigValue1.add(bigValue2);
		BigInteger mulResult = bigValue1.multiply(bigValue2);
		
		System.out.println("덧셉 : " + addResult);
		System.out.println("곱셈 : " + mulResult);

	}

}

 

d1 : 1.6
d2 : 0.1
d1 + d2 : 1.7000000000000002
d1 * d2 : 0.16000000000000003
두 실수의 덧셈결과: 1.7
두 실수의 곱셈결과: 0.16