Is there any way to set parameter default as function of previous parameter? [C++]

Question

I assume not, but I just wanted to check - is there any way in C++ to do something like the following? Obviously when I try the below I get a scope-based error about bar.

void foo(Bar bar, int test = bar.testInt) { ... }

Answer 1

If there is a value of test that is invalid, you could detect that:

void foo(Bar bar, int test = -1) { //assuming -1 is invalid
    if(test == -1) test = bar.testInt;

    //...
}

If not, you could always use overloaded functions:

void foo(Bar bar, int test) {
    //...
}

void foo(Bar bar) {
    foo(bar, bar.testInt);
}