File content as of revision 0:1d91b4046326:

#include <string>
#include <iostream>
#include <iomanip>

#include "MCP23017_I2C.h"

/*
 * Declare functions
 */
void AvailableIndicator(); // LED1 flashing for program while program is alive
DigitalOut g_availableLed(LED1); // To verify if program in running
Ticker g_available; // LED1 will flash with a period of 2s
char DisplayMenuAndGetChoice();

static CMCP23017_I2C g_gpioExp(p9, p10, 0x27, p15, p16, p17);

int main() {
    // Launch available indicator
    g_available.attach(&AvailableIndicator, 2.0);
    
    g_gpioExp.Initialize();

    while(true) {
        switch (DisplayMenuAndGetChoice()) {
            case 'a':
                g_gpioExp.write(GPB0, 1);
                break;
            case 'b':
                g_gpioExp.write(GPB0, 0);
                break;
            case 'c':
                g_gpioExp.write(GPB2, 1);
                break;
            case 'd':
                g_gpioExp.write(GPB2, 0);
                break;
            case 'r':
                g_gpioExp.reset();
                break;
            default:
                std::cout << "Invalid user choice\r" << std::endl;
                break;
        } // End of 'switch' statement
        
    } // End of 'while' loop
}

void AvailableIndicator()
{
    g_availableLed = !g_availableLed;
} // End of AvailableIndicator

char DisplayMenuAndGetChoice()
{
    char value;
    std::cout << "\r" << std::endl << "\r" << std::endl << "MCP23017_I2C v0.1\r" << std::endl;
    std::cout << "\tSet PortB-0   :\t\ta\r" << std::endl;
    std::cout << "\tUnset PortB-0 :\t\tb\r" << std::endl;
    std::cout << "\tUnset PortB-2 :\t\tc\r" << std::endl;
    std::cout << "\tUnset PortB-2 :\t\td\r" << std::endl;
    std::cout << "\tReset device  :\t\tr\r" << std::endl;
    std::cout << "Enter your choice: " << std::flush;
    value = getchar(); 
    std::cout << "\r" << std::endl;
    return value;
}