I\'ve been a bad programmer because I am doing a copy and paste. An example is that everytime i connect to a database and retrieve a recordset, I will copy the previous code and
The essence of code reuse is to take a common operation and parameterize it so it can accept a variety of inputs.
Take humble printf
, for example. Imagine if you did not have printf
, and only had write
, or something similar:
//convert theInt to a string and write it out.
char c[24];
itoa(theInt, c, 10);
puts(c);
Now this sucks to have to write every time, and is actually kind of buggy. So some smart programmer decided he was tired of this and wrote a better function, that in one fell swoop print stuff to stdout.
printf("%d", theInt);
You don't need to get as fancy as printf
with it's variadic arguments and format string. Even just a simple routine such as:
void print_int(int theInt)
{
char c[24];
itoa(theInt, c, 10);
puts(c);
}
would do the trick nickely. This way, if you want to change print_int
to always print to stderr you could update it to be:
void print_int(int theInt)
{
fprintf(stderr, "%d", theInt);
}
and all your integers would now magically be printed to standard error.
You could even then bundle that function and others you write up into a library, which is just a collection of code you can load in to your program.
Following the practice of code reuse is why you even have a database to connect to: someone created some code to store records on disk, reworked it until it was usable by others, and decided to call it a database.
Libraries do not magically appear. They are created by programmers to make their lives easier and to allow them to work faster.