I have used punch cards too during my last years of high school. We had to put our programs (500 to 3000 of punch cards) in a drawer in the afternoon to get them compiled during the night and get the results back the next day. You can imagine how long it tooks us to debug a program. You learn to be very efficient in writing bug free code . When I went to college I was amazed that I could actually use a terminal to enter my programs and get them compiled right away.