What is the point of external parameters?

Answer 1

they will used in every function.
they are also called global functions
example: if you have
int main(){int a = 10}
a+=10;
court << a << endl;

there will be an error saying a not declared.

the only way to do that is a reference tough

Answer 2

external parameter names are the ones that are used when calling an argument of that function. in swift, except for the first parameter(when the function has multiple parameters) it is mandatory to use external parameter names.

this is because usually the first parameter is indicated by the function name itself.