pset3 music- frequency returns zeroes

Question

I am having trouble with my code, I have spent a really long time trying to figure out why my code is only returning frequency with zeroes throughout. I would really appreciate if some could look at my code and see where my problem is. So far check50 has shown a smiley face for helpers.c compiles and bday text is correct, everything else is a frown.

Here is my code:

// Calculates frequency (in Hz) of a note int frequency(string note) { // TODO char note_letter = note[0]; int octave; int i= 0; char accidental = note[1];

if (strlen(note)==3)
{
    octave = atoi(&note[2]);

    if (accidental =='#')
    {
        i += 1;
    }
    else if (accidental == 'b')
    {
        i -= 1;
    }
}
else
{
    octave = atoi(&note[1]);
}

//check whether note letter and octave are contained within this range
float a=0., b=2., c=-9., d=-7., e=-5., f=-4., g=-2.;
if (note_letter< 'A' || note_letter> 'G')
{
    return true;
}
if (octave<0 || octave>8)
{
    return true;
}

switch (note_letter)
{
    case 'A':
    i=a;
    break;

    case 'B':
    i=b;
    break;

    case 'C':
    i=c;
    break;

    case 'D':
    i=d;
    break;

    case 'E':
    i=e;
    break;

    case 'F':
    i=f;
    break;

    case 'G':
    i=g;
    break;

    default:
    return true;

}

//position of octave
i += ((octave-4)*12);
octave -= 48;
float oct_power = i/12.;
int middle_note = 440;

//frequency
float freq = 0.0;
freq = round(middle_note * pow(2., oct_power));

return (freq);

}

Answer 1

It looks like there's some work to be done here. The frequency() function is supposed to "return as an int the note’s corresponding frequency, rounded to the nearest integer" according to the spec. The code that you referenced has a bunch of return true statements and at least one return false statement. True and false are bools. False will always return 0 and true will return a non-zero, usually 1, but not necessarily. In any case, these are not note frequencies! The return values must be the note frequencies!

If this answers your question, please click on the check mark to accept. Let's keep up on forum maintenance. ;-)

Answer 2

Try declaring the variables used in your frequency calculation as float instead of int. This should let you keep the precision until you round your final answer.