Suppose we can compile and execute our code at such a speed that a given line of code will be executed the very instant after we press run. In this case, a choi

Suppose we can compile and execute our code at such a speed that a given line of code will be executed the very instant after we press run. In this case, a choice printf line will execute at the same speed as typing print in our debugger. The benefit of the printf line is that we are in effect scripting our debugger to print some data every time that line is reached, without having to type it over and over. For one thing, this allows us to more easily go backwards in the execution, since we are really rerunning the program from scratch each time. We can also much more easily execute a whole litany of prints, which we can then scan for some expected data. The advantage of the debugger remains in the first place in languages that lack strong compile time reflection, such that only the debugger can reliably print the data we want to see, and in the second place in the myriad instances where we cannot get the compile+execution speed down to an acceptable time. I suppose debuggers are also useful when you have a core dump you want to analyze. Besides that I would consider the printf strictly superior.