Unlike our shampoo metaphor that we mentioned previously, which was wet hair, lather, rinse, and repeat, instead of repeating the instructions just once, you will repeat this cycle more than once.
Rarely will you be able to go through the program development cycle with only one iteration of it. Most likely, you will repeat parts of it many more times. You may edit the source code and compile it and find that the compiler failed. You will have to go back to edit the source code and compile it, each time figuring out what was wrong and then fixing it. Once it compiles successfully, you will move on to running and verifying it. If the output is not correct or the program crashes, you will have figure out what went wrong and start editing the source code again.
Does this sound frustrating? It can be – especially when you don't know why something went wrong or you can't figure out what the compiler or computer is saying is wrong.
Many, many years ago, when compilers were simpler and not as forgiving as they are today (actually, compilers are still not forgiving – they've just gotten better at figuring out what we humans may have done wrong with our programs and telling us in better ways!), the very first time I attempted to compile my Hello, world! program on a Digital Equipment Virtual Address Extension (VAX) Virtual Memory System (VMS) C compiler, the compiler gave me 23 thousand error messages. It turns out that I had overlooked a single ; somewhere. One character. Sheesh!
The point of that story is that you will make mistakes, mostly missing or erroneous punctuation or misspelled variables, and you will get frustrated. Part of learning to program is learning how to deal with your own frustration and how to become a sleuth to track down the picayune errors that will crop up.
Get up and away from the computer. Take a walk. Have a laugh. Get back to work. Don't omit the first parts (laughing and walking around a bit).
