File content as of revision 0:41b606c44f60:

#include "mbed.h"

DigitalOut led1(LED1);
DigitalOut led2(LED2);
DigitalOut led3(LED3);
DigitalOut led4(LED4);

int main() {
    unsigned char count = 0;
    while(1) {
        switch(count){
            case 0:
                led1 = 0;
                led2 = 0;
                led3 = 0;
                led4 = 0;
                break;
            case 1:
                led1 = 1;
                led2 = 0;
                led3 = 0;
                led4 = 0;
                break;
            case 2:
                led1 = 1;
                led2 = 1;
                led3 = 0;
                led4 = 0;
                break;
            case 3:
                led1 = 1;
                led2 = 1;
                led3 = 1;
                led4 = 0;
                break;
            case 4:
                led1 = 1;
                led2 = 1;
                led3 = 1;
                led4 = 1;
                break;
        }
        count++;
        wait(5.0);
        if(count > 4){
            count = 0;
        }
    }
}