Music helpers.c

// Helper functions for music

#include <cs50.h>
#include <stdio.h>
#include <math.h>
#include <string.h>

#include "helpers.h"

// Converts a fraction formatted as X/Y to eighths
int duration(string fraction)
{
    if (fraction[2] == 8)
    {
        if (fraction[0] == 1)
        {
            return 1;

        }
        else if (fraction[0] == 3)
        {
            return 3;

        }
        else if (fraction[0] == 8)
        {
            return 8;

        }

    }

    else if (fraction[2] == 4)
    {

    if (fraction[0] == 1)
    {
        return 2;
    }

    }

    else if (fraction[2] == 2)
    {
    if (fraction[0] == 1)
    {
        return 4;
    }

    }
    else
    {
        return 0;
    }
 return 0;
}

// Calculates frequency (in Hz) of a note
int frequency(string note)
{
    //char Alphaofnote = note[0];

    //Detetmining the Octave NO
    int OctaveNO = note[strlen(note)-1];
    OctaveNO -= 48; // Adjust Ascii to int value

    int noteoffset = 0; int accidentaloffset = 0;


    //Calculate the Noteoffset
    switch(note[0])
    {
        case 'A' :
        noteoffset = 0;
        break;

        case 'B' :
        noteoffset = 2;
        break;

        case 'C' :
        noteoffset = -9;
        break;

        case 'D' :
        noteoffset = -7;
        break;

        case 'E' :
        noteoffset = -5;
        break;

        case 'F' :
        noteoffset = -4;
        break;

        case 'G' :
        noteoffset = -2;
        break;

        default :
        return 0;
    }

    //Adjusting the accidental offset
    if (note[1] == '#')
    {
        accidentaloffset = 1;
    }

    else if (note[1] == 'b')
    {
        accidentaloffset = -1;
    }

    else
    {
        accidentaloffset = 0;
    }

int N = (12*(OctaveNO - 4) + noteoffset  + accidentaloffset)/12; // Generalized formula to determine n
    double freq = 440.0 * (pow(2.0, N));// freequency with respect to A4 note

int result = round(freq);
return result;

}


// Determines whether a string represents a rest
bool is_rest(string s)
{
    if (s == NULL)
    {
        return false;
    }

    else
    {
        return true;
    }
}