How to avoid code duplication with function overloading

Question

I have a pair of overloaded functions:

void func(const std::string& str, int a, char ch, double d) {
    // piece of code A
    sendMsg(str, a, ch, d);
    // piece of code B
}

void func(int a, char ch, double d) {
    // piece of code A
    sendMsg(a, ch, d);
    // piece of code B
}

piece of code A and piece of code B are exactly the same, the only difference is the parameter of sendMsg.

Is there some way to avoid the code duplication?

Answer 1

template may be a possibility:

template <typename ... Ts>
auto func(const Ts&... args)
-> decltype(sendMsg(args...), void()) // SFINAE to only allow correct arguments
{
    // piece of code A
    sendMsg(args...);
    // piece of code B
}

but moving // piece of code A in its own function would probably be my choice.

Answer 2

You would have to do something like

void codeA() {
    // ...
}

void codeB() {
    // ...
}

void func(const std::string& str, int a, char ch, double d) {
    codeA();
    sendMsg(str, a, ch, d);
    codeB();
}

void func(int a, char ch, double d) {
    codeA();
    sendMsg(a, ch, d);
    codeB();
}

Answer 3

Another idea would be to give a default value to str:

void func(int a, char ch, double d, const std::string& str = "")
{
    // piece of code A
    if (str.empty()) sendMsg(a, ch, d);
    else sendMsg(str, a, ch, d);
    // piece of code B
}