Very basic English-to-Morse converter (C++)

/*
* English to Morse converter
* 24/09/2011
* This program takes an English string and converts it to Morse code
*/

#include <iostream>
#include <map>
#include <string>
#include <cctype>

using namespace std;

void buildMorseMap();
void EnglishToMorse(string input);
map <std::string, std::string> morseMap;

int main(int argc, char **argv)
{

    buildMorseMap();

    string input;

    cout<<"Write one sentence: ";
    getline(cin,input); // Read in a whole line of text from the keyboard - this won't break if you use spaces as well

    EnglishToMorse(input);

    return (0);
}

// This function does the actual conversion
void EnglishToMorse(string input)
{

    // Convert the whole string to uppercase because there are no map entries for the lowercase originals
    for (int i=0; i<input.length(); i++)
    {
        input.at(i) = toupper(input.at(i));
    }

    string completedMorse; // Temporary string in which to store the completed Morse string for output

    for (int i=0; i<input.length(); i++)
    {
        string temp(1, input.at(i)); // Use a temporary string variable for the lookups, because the .at() function returns a primitive char rather than a string
        completedMorse.append(morseMap[temp]);
        completedMorse.append(" "); // Put a space in between each part of the Morse output
    }

    cout<<"Morse: "<<completedMorse<<endl;
}

// This function builds the Map container for storing the letter->Morse conversions
// This acts as a "lookup" table i.e. you can ask what the morse value for 'A' is and it'll tell you
// Mappings referred to at http://tcfreenet.org/people/calguire/morse.html
void buildMorseMap()
{
    morseMap.insert(std::make_pair("A",".-"));
    morseMap.insert(std::make_pair("B","-..."));
    morseMap.insert(std::make_pair("C","-.-."));
    morseMap.insert(std::make_pair("D","-.."));
    morseMap.insert(std::make_pair("E","."));
    morseMap.insert(std::make_pair("F","..-."));
    morseMap.insert(std::make_pair("G","--."));
    morseMap.insert(std::make_pair("H","...."));
    morseMap.insert(std::make_pair("I",".."));
    morseMap.insert(std::make_pair("J",".---"));
    morseMap.insert(std::make_pair("K","-.-"));
    morseMap.insert(std::make_pair("L",".-.."));
    morseMap.insert(std::make_pair("M","--"));
    morseMap.insert(std::make_pair("N","-."));
    morseMap.insert(std::make_pair("O","---"));
    morseMap.insert(std::make_pair("P",".--."));
    morseMap.insert(std::make_pair("Q","--.-"));
    morseMap.insert(std::make_pair("R",".-."));
    morseMap.insert(std::make_pair("S","..."));
    morseMap.insert(std::make_pair("T","-"));
    morseMap.insert(std::make_pair("U","..-"));
    morseMap.insert(std::make_pair("V","...-"));
    morseMap.insert(std::make_pair("W",".--"));
    morseMap.insert(std::make_pair("X","-..-"));
    morseMap.insert(std::make_pair("Y","-.--"));
    morseMap.insert(std::make_pair("Z","--.."));
    morseMap.insert(std::make_pair("1",".----"));
    morseMap.insert(std::make_pair("2","..---"));
    morseMap.insert(std::make_pair("3","...--"));
    morseMap.insert(std::make_pair("4","....-"));
    morseMap.insert(std::make_pair("5","....."));
    morseMap.insert(std::make_pair("6","-...."));
    morseMap.insert(std::make_pair("7","--..."));
    morseMap.insert(std::make_pair("8","---.."));
    morseMap.insert(std::make_pair("9","----."));
    morseMap.insert(std::make_pair("0","-----"));
    morseMap.insert(std::make_pair(",","--..--"));
    morseMap.insert(std::make_pair(".",".-.-.-"));
    morseMap.insert(std::make_pair("?","..--.."));
    morseMap.insert(std::make_pair(";","-.-.-"));
    morseMap.insert(std::make_pair(":","---..."));
    morseMap.insert(std::make_pair("/","-..-."));
    morseMap.insert(std::make_pair("-","-....-"));
    morseMap.insert(std::make_pair("()","-.--.-"));
    morseMap.insert(std::make_pair("_","..--.-"));
}