File content as of revision 0:a18d5bb52d85:

#include "mbed.h"

PwmOut myled1(LED1);
PwmOut myled2(LED2);
PwmOut myled3(LED3);
PwmOut myled4(LED4);

PwmOut * leds[4];

int main() {
    leds[0] = &myled1;
    leds[1] = &myled2;
    leds[2] = &myled3;
    leds[3] = &myled4;

    float level = 0;
    float increment = 0.01;
    int which = 0;
           
    while(1) {
        level += increment;
        
        if( level >= 1 ) { 
            *(leds[which]) = 1;
            which++;
            if( which > 3 ) {
                which = 3;
                increment = -0.01;
                wait(0.5);
            }
            else {
                level = 0;
            }
        }
        else if( level <= 0 ) {
            *(leds[which]) = 0;
            which--;
            if( which < 0 ) {
                which = 0;
                increment = 0.01;
                wait(0.5);
            }
            else {
                level = 0.999;
            }
        }
        
        *(leds[which]) = level;
        wait(0.01);
    }
}