Why do i can't add an string to an letter of another string?

Question

Consider the following code:

#include <iostream>
#include <typeinfo>

int main(){
    std::string word = "This is string";
    std::string word1 = "a" + word[0];
    std::cout << word1;
}

As you can see, i heve a string with the name word and i want to add first letter of it to another string and store them to string word1. when i run code, I expect that output is aT, but the output is ╨≥ ╨≥ ╨≥ ╨≥ P≥ ►≥ @≥ ╕♠≥ ! What does this mean? How do i fix it? (Also note that my IDE is Code::Blocks 20.03)

[Dupe that explains the problem](https://stackoverflow.com/questions/5705956/c-adding-string-literal-to-char-literal) and [Dupe that gives the solution](https://stackoverflow.com/questions/44369760/add-a-character-between-strings-in-c) — Jason, Aug 18 '22 at 10:12
*"i heve a string with the name `word` and i want to add first letter of it to another string and store them to string `word1`."* -- more precisely: you have a `std::string` with the name `word` and you want to add the first letter of it to a **string literal** and store them to `std::string` `word1`. — JaMiT, Aug 18 '22 at 10:27

score 3 · Accepted Answer · answered Aug 18 '22 at 10:07

3

"a" is not a string (well, its a c-string, but not a std::string, and a c-string is just an array). Its a const char[2] and decays to a pointer when + is applied. There is an operator+ for std::string though:

std::string word1 = std::string("a") + word[0];

or

std::string word1 = "a"s + word[0];

answered Aug 18 '22 at 10:07

463035818_is_not_an_ai

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Thanks, But even if i change "a" to "ab", i get that error again Although "ab" is not char. – Just a homo sapiens Aug 18 '22 at 10:11
@Amin `"ab"` is a c-cstring, a `const char [3]`, just like `"a"` is a `const char [2]`. A `char` literal is `'a'`, but adding `char` wont works as well. Adding two `char`s adds their numerical value, it does not concatenate them to a string – 463035818_is_not_an_ai Aug 18 '22 at 10:12
@Amin note the `"a"s` in the answer, which makes it a `std::string`. – Jesper Juhl Aug 18 '22 at 13:25

Why do i can't add an string to an letter of another string?

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