Calculate and print table of notes and frequencies for MIDI note numbers

midi_note_list.c

#include <stdio.h>
#include <math.h>

/***********
 * Calculate and print note names, octaves and frequency for MIDI notes
 *
 * gcc -lm -o midi_note_list midi_note_list.c
 *
 * UNLICENCE (see end)
 *
 ************/

void main()
{
    float frequency;
    int midinote ;
    //char notes[12][20] = {"A","A#","B","C","C#","D","D#","E","F","F#","G","G#"};
    char notes[12][20] = {"A","B♭","B","C","D♭","D","E♭","E","F","G♭","G","A♭"};
    int noteindex ;
    int noteoctave ;
    printf("midi note frequency \n"); 
    for ( midinote = 0; midinote < 128 ; midinote++)
    {
        //calc frequency
        //  f = 440 * 2 ^ (n -69)/12
        frequency = 440 * powf( 2, ( ((float) midinote - 69)/12 )) ;
        noteoctave = (( midinote - 12) / 12); // calculate octave #
        noteindex  = (( midinote + 3) % 12);  // calculate name of note
        if (midinote >= 12) 
        {
            printf("%3d  %2s%d  %8.2f\n", midinote, notes[noteindex],noteoctave,frequency);
        }
        else
        {
            printf("%3d  ---  %8.2f\n", midinote, notes[noteindex], noteoctave,frequency);
        }
    }
}

/*
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of this software dedicate any and all copyright interest in the
software to the public domain. We make this dedication for the benefit
of the public at large and to the detriment of our heirs and
successors. We intend this dedication to be an overt act of
relinquishment in perpetuity of all present and future rights to this
software under copyright law.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
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ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

For more information, please refer to <https://unlicense.org>
 */