import java.math.BigDecimal;
public class Test12 {
	static final int location=10;
	public BigDecimal add(double value1,double value2){
		BigDecimal b1 = new BigDecimal(Double.toString(value1));
		BigDecimal b2 = new BigDecimal(Double.toString(value2));
		return b1.add(b2);
	}
	
	public BigDecimal sub(double value1,double value2){
		BigDecimal b1 = new BigDecimal(Double.toString(value1));
		BigDecimal b2 = new BigDecimal(Double.toString(value2));
		return b1.subtract(b2);
	}
	
	public BigDecimal mul(double value1,double value2){
		BigDecimal b1 = new BigDecimal(Double.toString(value1));
		BigDecimal b2 = new BigDecimal(Double.toString(value2));
		return b1.multiply(b2);
	}
	
	public BigDecimal div(double value1,double value2){
		return div(value1,value2,location);
	}
	
	public BigDecimal div(double value1,double value2,int b){
		if(b<0){
			System.out.println("b值必须大于等于0");
		}
		
		BigDecimal b1=new BigDecimal(Double.toString(value1));
		BigDecimal b2=new BigDecimal(Double.toString(value2));
		return b1.divide(b2,b,BigDecimal.ROUND_HALF_UP);
	}
	
	public static void main(String[] args) {
		
		Test12 b=new Test12();
		System.out.println("相加："+b.add(-7.5, 8.9));
		System.out.println("相减："+b.sub(-7.5, 8.9));
		System.out.println("相乘："+b.mul(-7.5, 8.9));
		System.out.println("相除，保留10位小数："+b.div(10, 2));
		System.out.println("相除，保留5位小数："+b.div(-7.5, 8.9, 5));
	}
}