Homework: A Logic bug in my C# code, What Should I do ....?

Question

Hi I'm Having a logical error

Now I provided the following as input

the Salary i input the salary 30000

the No. Child 9

so the so the net salary will be

the family bonus + salary - tax
     (750)       + (30000) - (3000)

but my program count them as 
      (1500)    + (30000) + (6000)

my program doubled ( accumulate ) the family bonus and the tax

I hope I explain right

Answer 1

Another problem seems to lie in the fact that you don't initialize familybonus when you say familybonus += 300. So everytime you call GetFamilybonus it's added to the previous result. You call it twice in the PrintEmployee function, once directly and once indirectly by calling getNet;

Answer 2

I took the existing code, and hard-wired the inputs (rather than using Console.ReadLine()), I get:

You are 28 years old Salary= 30000 Tax= 3000 Family bonus= 750 Net= 25500

The main problem seems to be not initializing values - i.e. treating fields as variables:

public double getTax()
{
    if (Salary < 10000)
        tax = 0;
    if (Salary <= 10000 && Salary >= 20000)
        tax += Salary * 0.05;
    else tax += Salary * 0.1;
    return tax;
}

OK - and what does tax start at if Salary >= 10000, etc. Likewise familyBouns in getFamilyBonus. By the way, how can Salary be both <= 10000 and >= 20000?

To illustrate, I've changed the output to:

    Console.WriteLine("Tax= {0}", getTax());
    Console.WriteLine("Tax= {0}", getTax());
    Console.WriteLine("Tax= {0}", getTax());

Which shows:

Tax= 3000 Tax= 6000 Tax= 9000

My advice would be: don't store calculated values unless you know the math is so complex that it is worth it. Just calculate them as needed (no field at all).