BigInteger and BigDecimal

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import java.math.BigInteger;

public class Print1ToMaxOfNDigits {


	public static void main(String[] args) {

		// print1ToMaxDigits("9");
		BigInteger bigInteger1 = new BigInteger("999999999999999999999999");
		BigInteger bigInteger2 = new BigInteger("999999999999999999999998");

		// add
		bigInteger1 = bigInteger1.add(bigInteger2);
		System.out.println(bigInteger1);

		// subtract
		bigInteger1 = bigInteger1.subtract(bigInteger2);
		System.out.println(bigInteger1);

		// multiplay
		bigInteger1 = bigInteger1.multiply(bigInteger2);
		System.out.println(bigInteger1);

		// divide
		bigInteger1 = bigInteger1.divide(bigInteger2);
		System.out.println(bigInteger1);

		// negate 取相反数
		bigInteger1 = bigInteger1.negate();
		System.out.println(bigInteger1);
	}
}

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import java.math.BigDecimal;
/*
 * 构造方法:
 * 		public BigDecimal(String val):
 * 成员方法:
 * 		public BigDecimal add(BigDecimal augend):加
 * 		public BigDecimal subtract(BigDecimal subtrahend):减
 * 		public BigDecimal multiply(BigDecimal multiplicand):乘
 * 		public BigDecimal divide(BigDecimal divisor):除
 * 		public BigDecimal divide(BigDecimal divisor,int scale,int roundingMode):商,几位小数,如何舍取。
 * 		
 */
public class BigDecimalDemo {
	public static void main(String[] args) {
		System.out.println(0.09 + 0.01);
		System.out.println(1.0 - 0.32);
		System.out.println(1.015 * 100);
		System.out.println(1.301 / 100);

		// public BigDecimal add(BigDecimal augend):加
		BigDecimal bd1 = new BigDecimal("0.09");
		BigDecimal bd2 = new BigDecimal("0.01");
		System.out.println("add:" + bd1.add(bd2));
		System.out.println("----------------------");
		// public BigDecimal subtract(BigDecimal subtrahend):减
		BigDecimal bd3 = new BigDecimal("1.0");
		BigDecimal bd4 = new BigDecimal("0.32");
		System.out.println("subtract:" + bd3.subtract(bd4));
		System.out.println("----------------------");
		// public BigDecimal multiply(BigDecimal multiplicand):乘
		BigDecimal bd5 = new BigDecimal("1.015");
		BigDecimal bd6 = new BigDecimal("100");
		System.out.println("multiply:" + bd5.multiply(bd6));
		System.out.println("----------------------");
		// public BigDecimal divide(BigDecimal divisor):除
		BigDecimal bd7 = new BigDecimal("1.301");
		BigDecimal bd8 = new BigDecimal("100");
		System.out.println("divide:" + bd7.divide(bd8));
		System.out.println("divide:" + bd7.divide(bd8,3,BigDecimal.ROUND_HALF_UP));
		System.out.println("divide:" + bd7.divide(bd8,9,BigDecimal.ROUND_HALF_UP));
	}
}