Speaker program

#include <iostream>
#include <windows.h>

using namespace std;

void sounds(string music);
string Convert_upper(string word);

int main()
{
    string music;
    cout << "Input string for playing" << endl;
    getline(cin, music);
    string upper = Convert_upper(music);
    sounds(upper);
}

string Convert_upper(string word)
{
    string final;
    for (int i = 0;i<word.size();i++)
    {
        final += toupper(word[i]);
    }
    return final;
}


void sounds(string music)
{
    for (int i = 0;i<music.size();i++)
    {
        switch(music[i])
        {
        case 'A' : Beep(220,200);
        case 'B' : Beep(250,200);
        case 'C' : Beep(260,200);
        case 'D' : Beep(300,200);
        case 'E' : Beep(330,200);
        case 'F' : Beep(350,200);
        case 'G' : Beep(400,200);
        }
    }
}