function prototype and definition question

[GUnit216]

Im a beginner in C++ and I have this program here:

#include <iostream>
#include <vector>
#include <cmath> //abs()

using namespace std;

void RotateLetters (vector <char> & CharList, int NumPositions);

int main (void)
{
vector <char> Alphabet (26);

for (int cnt = 0; cnt < 26; cnt++)
Alphabet [cnt] = char (cnt + ‘A’);

cout << “How many positions do you intend to rotate this alphabet list? “
<< “ ‘-‘ means rotate upward; otherwise downward.” << endl;

int Positions;

cin >> Positions;

RotateLetters (Alphabet, Positions);

for (cnt = 0; cnt < Alphabet.size(); cnt++)
cout << Alphabet[cnt];

cout << endl;

return 0;
}
//Purpose: Rotate the letters in CharList either upward or downward depending
// on the sign of the integer argument
//Precondition: CharList is a char vector containing the 26 alphabetical letters,
// NumPositions is the desired position for the 26 letters to rotate –
// ‘+’ or no sign => downward and ‘-‘ => upward
//Postcondition: The CharList vector is rotated accordingly

void RotateLetters (vector <char> & CharList, int NumPositions)


How do I supply the function prototype and definition for the function RotateLetters() ????

[amac]

Well you already have the function's prototype. You just need to give it's definition.

Like so.

void RotateLetters (vector <char> & CharList, int NumPositions) 
{
    // Rotate characters here.
    return;
}

It is defined in the same manner as main().