# Pset3/Music can't check until a frown turns upside down

i got this message when i tried to check50 of music problem "can't check until a frown turns upside down", i couldn't find what is cause of the problem, so i'll be thankful if someone give me a hand

``````    // Helper functions for music
#include <cs50.h>
#include <stdio.h>
#include "helpers.h"
#include <math.h>
#include <string.h>

// Converts a fraction formatted as X/Y to eighths
int duration(string fraction)
{
int nom = fraction[0] - 48;
int dom = fraction[2] - 48;
int num = (8 * nom) / dom;
return num;
}

// Calculates frequency (in Hz) of a note

int frequency(string note)
{
note = get_string();
int note_letter = note [0];
int octave = note [strlen(note) - 1] - '0';
unsigned int move_octave = octave - 4;
float freq = 440;
char semi = note [1];
float a = 0.0, b = 1.0, c = -9.0, d = -7.0, e = 5.0, f = 4.0, g = 2.0;
float n = 0;

freq *= (pow(2, move_octave));

switch(note_letter)
{
case 'A':
n = a;
break;
case 'B':
n = b;
break;
case 'C':
n = c;
break;
case 'D':
n = d;
break;
case 'E':
n = e;
break;
case 'F':
n = f;
break;
case 'G':
n = g;
break;
}

freq *= pow(2.0, n/12.0 );

if (semi == 'b')
{
freq /= (powf(2.0, (1.0/12.0))); //b lower semitone
}
else if (semi == '#')
{
freq *= (powf(2.0, (1.0/12.0))); //# higher semitone
}
freq = round(freq);

return freq;
}

// Determines whether a string represents a rest
bool is_rest(string s)
{
string rest = s;
char new_line = '\n';

if (strcmp (rest, &new_line) == 0)
{
return true;
}
else
{
return false;
}
}
``````