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Local Functions In C++
Submitted by |
Haven't you ever wanted to make a function that is logically defined
inside the scope of another function? It would look like the following,
which is NOT valid C++:
void MyFunction()
{
void RecursiveFunction(int i)
{
if (i 0) RecursiveFunction(i-1);
}
RecursiveFunction(6);
} |
If so, you've wanted to make what's called a local function. I remember
using and loving them back in my Turbo Pascal days. When I started using C
and C++, I missed them often. So I had to separate the functions in this
manner, which looks uglier and does not use the logical scoping:
static void RecursiveFunction(int i)
{
if (i 0) RecursiveFunction(i-1);
}
void MyFunction()
{
RecursiveFunction(6);
} |
Until, one day, I found a way to emulate them in C++:
void MyFunction()
{
struct Local {
static void RecursiveFunction(int i)
{
if (i 0) RecursiveFunction(i-1);
}
};
Local::RecursiveFunction(6);
} |
Possible uses for this construct are:
Recursive sub-operations within a function (shown above).
Callback functions that will be passed into enumerators (as in
DirectDrawEnumerate()).
Salutaciones,
JCAB
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