I am learning to program in C using the “Head First C” book by David Griffiths & Dawn Griffiths. But this is not the first time I used this book, for several times until now, I cannot even complete the book. Maybe this time I will.

How to compile a C program with gcc?

> gcc hello.c -o hello

In C functions, what is pass-by-value vs. pass-by-reference?

All function arguments are technically passed by value, which can only modify a local copy of the variable (i.e., function scope).

The alternative (i.e., pass-by-reference) is enabled using pointers, which can modify the value of a variable outside of the function’s scope.