Need help with a C++ program?

Hey guys I have a program that I need to write and I have no idea how to do it:


this program has to prompt the user in a menu to encrypt a message, decrypt or quit.


I'm supposed to use functions in this program


This is what i am supposed to use without removing any parts, just adding things where needed.


#include%26lt;iostream%26gt;


using namespace std;





int menu();


void encrypt(int);


void decrypt();








int main(){





int choice;


int shift = 7; // default shift


choice = menu();


while (choice != 3){


if (choice == 1){


cout %26lt;%26lt; "Enter the 'shift' value: ";


cin %26gt;%26gt; shift;


encrypt(shift); }


else


decrypt();





cout%26lt;%26lt;endl%26lt;%26lt;endl%26lt;%26lt;endl;


choice = menu();


}


return 0;


}


I don't even know how to get started functions kind of confuse me


Can someone at least point me in the right direction?

Need help with a C++ program?
You will need to write two functions. I'm not really sure what the shift is, but to get started, do this:





void encrypt(int shift)


{


//Use code in here to translate the value. I'm guessing the shift


//value, since it is an integer will return a letter, so therefore


//use a switch to print out the letter:





switch (shift)


{


case 1:


cout %26lt;%26lt; "k ";


break;





case 2:


cout %26lt;%26lt; "n ";


break;





//... and so on for each value


}//End Switch


}//End Encrypt





//The decrypt is going to need to take in a string, and return


//numbers that correspond to that string.





void decrypt()


{


string sIn="";





//Get a value for this string


cout%26lt;%26lt;"Enter the string to be decrypted:";


cin%26gt;%26gt;sIn;





//Get a number value for each letter:


for (int x=0; x %26lt; sIn.length(); x++)


{


//Get the next letter in order


string sTemp = sIn.substr(x,1);








//Convert this letter to a number and output that number


switch (sTemp)


{


case "k":


cout %26lt;%26lt; "1 ";


break;





case "n":


cout %26lt;%26lt; "2 ";


break;





//...and so on


}//End Switch


}//End For loop


}//End decrypt











That should get you started. Good luck!!