Why is the
init function in fifteen not declared as
void init(int), since it uses the integer
int variable named
d is a global variable. Global variables are variables that are declared outside of any functions. They can be accessed from anywhere in the source code file and that's why we don't need the function
init to accept an
int as an argument — because we can access
d directly inside it.
Usually we use global variables when we need to access a variable from multiple functions as it's the case with the variable
d. This is regarded as a better approach than passing the same variable to multiple functions as an argument again and again as we'd make a copy of that variable every time we pass it to a function.