无正常返回值-抛异常

public class Demo8_2 {
	public static void main(String[] args) {
		LinearEquation li=new LinearEquation(1, 1, 1, 1, 5, 6);
		System.out.println(li.getX());
		System.out.println(li.getY());
	}
}
class LinearEquation{
	private double a,b,c,d,e,f,delt;
	public LinearEquation(double a,double b,double c,double d,double e,double f) {
		 //函数传进了a,b,c,d,e,f这6个值，把值赋给全局变量
		this.a=a;
		this.b=b;
		this.c=c;
		this.d=d;
		this.e=e;
		this.f=f;
	}
	public boolean isSolvable(){
		return (delt=a*d-b*c)!=0;
	}
	public double getX(){
		if(isSolvable()){
			return (e*d-b*f)/delt;
		}else{
			//System.out.println(\"The equation has no solution\");
			/**/必须返回以个double型的数据，但此时无解，没有正常可以返回的值
			//即如果出错了，需要抛异常**
			throw new IllegalArgumentException(\"The equation has no solution\");
		}
	}
	public double getY(){
		if(isSolvable()){
			return (a*f-e*c)/delt;
		}else{
			//System.out.println(\"The equation has no solution\");
			throw new IllegalArgumentException(\"The equation has no solution\");	
			//类似将throw当做return 
		}	
	}
	public double getA(){
		return a;
	}
	public double getB(){
		return b;
	}
	public double getC(){
		return c;
	}
	public double getD(){
		return d;
	}
	public double getE(){
		return e;
	}
	public double getF(){
		return f;
	}
}

结果：Exception in thread “main” java.lang.IllegalArgumentException: The equation has no solution
at LinearEquation.getX(Demo8_2.java:30)
at Demo8_2.main(Demo8_2.java:5)