In c++, where should constant strings be placed?

Development Programming & Scripting C++
, , , ,
1

In c++, where should constant strings be placed?

In Java, you can write an Interface, where you put all the constant strings

What about ue c++?

2

For what purpose? You can define static const strings or FNames in cpp files (doesn’t have to be part of a class or interface). If you’re thinking about localization, this page might be helpful Text Localization | Unreal Engine Documentation

3

In fact, it is for unified management

Such as:

a.cpp

void Test(TMap<FString, UObject*> Map){
  UObject* obj = Map["Name"]
}

b.cpp

void Test(TMap<FString, UObject*> Map){
  UObject* obj = Map["Name"]
}

The same Map is used in different files, I want key to be a constant string, Easy to maintain

4

Sure that’s fine. In a header which you include in multiple cpp files:

// Declare the constant string:
extern const FString SomeString;

In a single cpp file:

#include "SomeString.h"
// Define the constant string:
const FString SomeString = "Something";

In any cpp file:

#include "SomeString.h"

// Use the constant string:
void Test(const TMap<FString, UObject*>& Map){
  UObject* obj = Map[SomeString];
}

Some other tips:

  • Pass TMap (and other containers like TArray) by reference, like const TMap<...> & Param or TMap<...> & Param if you want to modify it. Otherwise you’re copying the container every time you pass it as an argument to a function.
  • Use FName rather than FString for these. It’s much faster to compare names than strings and they’re a natural fit for TMap keys for this reason.
2 Likes
5

Possibly better to use #define for these as well, rather than allocating additional memory for the consts.

6

thank you ~~~