mini tank

hello everyone im in the middle of making a robot which uses an arduino and an ultra sonic sensor (clone of ping so it has the same pinouts) ive got the robot and i have a code but the code has servos an one of my servos just broke so i was wondering if it was possible to convert this code to a code that uses dc motors ive tried this a couple times but i havent had any luck heres i tried pasting my current code but i just ended landscape format?? first is this code even correct and can i change it to one that uses dc motors?also might i need a motor shield im pretty sure mines busted. and one last thing which pins on the arduino do i connect the motors to? ive looked online with no useful information thanks alot

hello again heres a little update since chuckcrunch is making a robot like mine but his has a servo i put one on mine too also ive got my motor shield