Writing a Computer program (in any language) is sort of like Training your dog to do something

But, it doesn't have the natural sense that any normal dog would have. It doesn't know how to protect itself, it's hardware, you, a tree, a person, a group of people, a dog or dogs or group of dogs or horse or cow or group of cows. 

That is why we say, "Garbage in Garbage out" and if you don't know you wrote garbage because logical details got left out, hopefully you find out what the problems are before someone dies from that program, especially if that program is running in a car or truck, or heavy equipment that is trying to self drive itself or dig holes or whatever it is doing like building vehicles or things of all sorts.