About function declarations in functions

We can have function declarations inside of function bodies:

void f(double) {
    cout << "f(double) called";

void f(int) {
    cout << "f(int) called";

void g() {
    void f(double); //Functions declared in non-namespace scopes do not overload
    f(1);           //Therefore, f(1) will call f(double)                  

This can be done in order to hide a function such as f(int) in this case, but my question is: Is this really the only reason why it is possible to declare a function inside of another?

Or in other words:
Does the possibility of declaring a function inside of a function exist for the sole purpose of hiding a function?

>Solution :

This can also be used to limit the visibility of a function declaration to only one specific function. For example:


#include <iostream>
void f(double d) {
    std::cout << d << '\n';


int main() {
   void f(double);
   f(1); // prints 1

void g() {
    f(2); // error: 'f' was not declared in this scope

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