赋值的左侧不是变量？

Question

I am trying to set this up so my tests will work but I keep getting an error about the left-hand side of the assignment is not a variable on the line starting with 'flunking.gpa...'. Any suggestions as to what i am doing wrong?

/**
 * After we have added hours and quality points, we need to 
 * check that the gpa is (quality points) / hours
 */ 
@Test
public void gpa() {  
    flunking.gpa() = flunking.qualityPoints() / (double)flunking.hours();
    assertEquals(flunking.gpa(), 0.0, DELTA);
}

Answer 1

You're attempting to assign a value to a method

flunking.gpa() = flunking.qualityPoints() / (double)flunking.hours();

As both qualityPoints and hours contain values within the flunking classs, there's should be no need for any assignment here, ie just have gpa return the calculated value in that class as required, eg

public double getGPA() {
   return qualityPoints / (double)hours; 
}

Answer 2

Perhaps there is a flunking.setGpa(newValue) or flunking.gpa(newValue) method to change the value? .gpa() just returns the value and it doesn't make sense to assign to it, technically speaking.