Passing a character string to a function parameter in C

Question

Bear with me as I am relatively new to C.

I am trying to create a function, which could take the names of musical notes (i.e. D or D#) as an argument, and return the value of their corresponding midi note number (midi number table) with a second argument for octave.

However, I seem to be having problems with either the initialisation of the string, or using it within the function. This is the function I wrote:

int midi_number(char note[], int octave)
{
    int midiNumber

    if (note[1] = '#')
    {
        switch(note[0])
        {
        case 'C': case 'c':
        midiNumber = 25;
        break;
        case 'D': case 'd':
        midiNumber = 27;
        break;
        ...
        }
    }
    else
    {
        switch(note[0])
        {
        case 'C': case 'c':
        midiNumber = 24;
        break;
        case 'D': case 'd':
        midiNumber = 26;
        break;
        ...
        }
    }
    return (midiNumber + (octave * 12))
}

I am then calling the function as follows:

midi_number('C#', 1);

Hopefully this gets across the idea of what I'm trying to achieve. I have researched into pointers and arrays, but I can't see how it applies to what I am doing.

Any help massively appreciated!

You use single quotes `'` for *character* literals, and double quotes `"` for string literals. — Some programmer dude, Apr 05 '16 at 16:58
This won't even compile. Mismatched types, missing semicolon, etc. — interjay, Apr 05 '16 at 16:58
Also, think about the difference between comparison and assignment operators. — Some programmer dude, Apr 05 '16 at 16:58
Both of my above points should have been explained by almost any good beginners book. Maybe you should throw out the one you have and [find another one](http://stackoverflow.com/questions/562303/the-definitive-c-book-guide-and-list)? — Some programmer dude, Apr 05 '16 at 16:59

score 0 · Accepted Answer · answered Apr 05 '16 at 17:00

0

note[1] = '#' is assigning '#' to note[1], not comparing them.

You need note[1] == '#' inside your if statement.

answered Apr 05 '16 at 17:00

Ewan Mellor

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Thanks! very stupid mistake. That, plus cleaning up the syntax problems has got it working. – Harvs Apr 05 '16 at 17:18

Passing a character string to a function parameter in C

1 Answers1