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ChausseBenjamin/note2hertz.cpp

Last active January 16, 2023 02:19
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  1. ChausseBenjamin revised this gist Jan 16, 2023. 1 changed file with 8 additions and 0 deletions.
    8 changes: 8 additions & 0 deletions note2hertz.cpp
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    Original file line number Diff line number Diff line change
    @@ -2,6 +2,14 @@
    #include <math.h>
    #include <algorithm>

    // note string structure:
    // [A-G][0-9][f,n,s]
    // A-G: Note entre La (A) et Sol (G)
    // 0-9: Octave du piano
    // f: bémol (flat), n: naturel, s: dièse (sharp)
    // Donc "D3s" va jour le troisième Ré dièse du piano


    // list of notes and list of their corresponding frequencies
    string note_names[] = {
    "A", "A#", "B", "C",
  2. ChausseBenjamin created this gist Jan 16, 2023.
    47 changes: 47 additions & 0 deletions note2hertz.cpp
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    Original file line number Diff line number Diff line change
    @@ -0,0 +1,47 @@
    #include "note.h"
    #include <math.h>
    #include <algorithm>

    // list of notes and list of their corresponding frequencies
    string note_names[] = {
    "A", "A#", "B", "C",
    "C#", "D", "D#", "E",
    "F", "F#", "G", "G#"
    };

    float note_hertz[] = {
    440.0, 466.16, 493.88, 523.25,
    554.37, 587.33, 622.25, 659.25,
    698.46, 739.99, 783.99, 830.61
    };

    float Note::getHertz(){
    // calculate the frequency of the note in hertz
    // based on the note string.
    // The tuning is A4 = 440 Hz, equal temperament
    // get the note modifier (sharp, flat, natural)
    char modifier = note[note.length()-1];
    int offset;
    switch (modifier) {
    case 's': offset = 1; break;
    case 'f': offset = -1; break;
    case 'n': offset = 0; break;
    default: offset = 0;
    }
    // get the octave value
    int octave = note[note.length()-2] - '0';
    octave -= 4;
    // Get the first character of the note string
    string note_name = note.substr(0, 1);
    // Find the note in the note_names array and adjust the offset
    int index = find(note_names, note_names + 12, note_name) - note_names + offset;
    // if the note index is below 0, lower the octave by 1 and add 12 to the index
    // if the note index is above 11, raise the octave by 1 and subtract 12 from the index
    switch (index) {
    case -1: octave--; index = 11; break;
    case 12: octave++; index = 0; break;
    };
    // calculate the frequency of the note
    // based on the note index and the octave
    float hertz = note_hertz[index] * pow(2, octave);
    }