File content as of revision 0:105a5c050cb4:

#include "mbed.h"

DigitalIn halls (p8);
DigitalIn pushb (p20);
DigitalOut l1(LED1);
DigitalOut l2(LED2);
DigitalOut l3(LED3);
DigitalOut l4(LED4);
Serial pc(USBTX,USBRX);

int main() {
    while(1) {
        wait(1);
        int hall;
        int push;
        halls.read();
        pushb.read();
        hall=!halls;
        push=pushb;
        int button=hall+push;
        switch(button){
            case 0:
                l1=1;
                l2=0;
                l3=0;
                l4=0;
                break;
            case 1:
                if (push==0) {
                    l1=0;
                    l2=1;
                    l3=0;
                    l4=0;
                }
                else {
                    l1=0;
                    l2=0;
                    l3=1;
                    l4=0;
                }
                break;
            case 2:
                l1=0;
                l2=0;
                l3=0;
                l4=1;
                break;
        }
    }  
}