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?
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.
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(); } 
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 } 
const std::string& also with a default.sendMsg(str,a,ch,d) when str == "" (but not the default one). Thats why I suggest to use std::optional instead (though we don't know what sendMsg is, it may not matter)
Of course, use a functor:
template <typename F> void func2(F&& f) { // piece of code A f(); // piece of code B } Usage:
void func(int a, char ch, double d) { func2([&](){ sendMsg(a, ch, d); }); } A bit of explanation: Currently accepted answer is totally fine when you need to call the exactly same code with different parameters. But when you need to "inject" an arbitrary code (possibly a multiple pieces of arbitrary code) into another function, passing a temporary lambda is your best bet. Conceptually, what receiving function is seeing/getting is some abstract "callable" object (in fact, it can be anything with operator (), not just lambda) which it calls at due time. And since its a templated function, it will be compiled into zero-overhead code "as if" actual code was copy-pasted in there. The usage part is simply shows a c++ syntax to create a callable with arbitrary code in-place (I advise to read language references/tutorials on lambdas to understand the internals better).
sendMsg . This is of an issue with the question rather the solution here.
sendMsgis a library function, which does some socket job. I can't change it anyway.not suitable for my caseis best prove of that.