UI programming - let's take websites - the DOM can be considered an API. Game development, using literally any pre-existing function can be considered an API (

UI programming - let's take websites - the DOM can be considered an API. Game development, using literally any pre-existing function can be considered an API (libraries are APIs). This really boils down to saying - the average line of code is used many times. How many, I guess, depends on how poorly designed the APIs are. If the average function takes longer to use than it did you write (I'm skeptical) - then it would be <9 usages per line. If it takes less time to use a function than to write it - then it would be >9 times.