File content as of revision 0:55150494d6db:

#include "mbed.h"

DigitalOut led_red(LED_RED);
DigitalOut led_green(LED_GREEN);
DigitalOut led_blue(LED_BLUE);
DigitalIn sw2(SW2);
DigitalIn sw3(SW3);
Serial pc(USBTX, USBRX);

int check_sw2(int choice)
{
    if(sw2 == 0)
    {
        pc.printf("SW2 button pressed. \n");
        switch(choice)
        {
            case 0:
                led_red = 0;
                led_green = 1;
                break;
            case 1:
                led_red = 1;
                led_green = 0;
                 break;
            case 2:
                led_red = 0;
                led_green = 0;
                break;
            case 3:
                led_red = 1;
                led_green = 1;
                break;
        }
        choice++;
        if(choice > 3) choice = 0;
    }
    return choice;
}

void check_sw3(DigitalOut led_status)
{
    if(sw3 == 0) 
    {
        pc.printf("SW3 button pressed. \n");
        if(led_status) led_blue = 0;
        else led_blue = 1;
    }
}

int main()
{
    int choice = 0;
    
    led_green = 1;
    led_red = 1;
    led_blue = 1;
 
    pc.baud(115200);
    pc.printf("Hello World from FRDM-K64F board.\n");

    while(true)
    {
        choice = check_sw2(choice);
        check_sw3(led_blue);
        wait(0.3);       
    }
}