Is there any way to tell C++11 to use std::string instead of const char*?

Question

Im trying to migrate code from another language that allows concatonation of strings with the '+' operator.

//defintion 
void print(std::string s) {
    std::cout << s;
}
//call
print("Foo " + "Bar");

The issue I'm having is that c++ sees "Foo " and "Bar" as const char* and cannot add them, is there any way to fix this. I have tried including the string library to see if it would change them automatically but that didnt seem to work.

Does this answer your question? [How to concatenate two strings in C++?](https://stackoverflow.com/questions/15319859/how-to-concatenate-two-strings-in-c) — Michael Hall, May 06 '21 at 04:42
not an answer, but do pass strings between functions as `const std::string& s` instead of as `std::string s`. Avoids a copy and enables opitimizations. — selbie, May 08 '21 at 07:44

score 5 · Accepted Answer · edited May 05 '21 at 23:15

5

In c++14 and later:

using namespace std::literals;
print("Foo "s + "Bar");

In c++11:

std::string operator "" _s(const char* str, std::size_t len) {
    return std::string(str, len);
}

print("Foo "_s + "Bar");

Or, in all versions:

print(std::string("Foo ") + "Bar");

edited May 05 '21 at 23:15

Remy Lebeau

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answered May 05 '21 at 22:45

Yakk - Adam Nevraumont

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1

This is a good solution in general, but as the OP said in comment: "*I forgot to mention that I was in c++11*", so this won't work for the OP specifically. – Remy Lebeau May 05 '21 at 22:45

score 5 · Answer 2 · answered May 05 '21 at 22:50

5

The easiest solution for the case of 2 string literals:

print("Foo " "Bar");

Otherwise:

print(std::string("Foo ") + "Bar");

answered May 05 '21 at 22:50

rustyx

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Is there any way to tell C++11 to use std::string instead of const char*?

2 Answers2