There is an error with my function parameters (handling string)

[Ardeshir81]

HI!
This is my code :

string onetwo (string input)
{
    return "hi" ;
}

int main ()
{
    string input ;
    cin >> input ;
    cout << onetwo (input [0] + input [1]) ;
}

I don't think any additional explanations are needed , when I click the build button , this error appears on line 10:

"invalid conversion from 'int' to 'const char' [-fpermissive]"
Codeblocks 12.11 GCC MinGW

[vlad from moscow]

Let consider the expression

input [0] + input [1]

the left and the right operands have type char. According to the C++ Standard when an additive operator is used "

The usual arithmetic conversions are performed for operands of arithmetic or enumeration type.

"
That means that input[0] and input[1] are converted to type int and the result has the same type int. There is no such a constructor in class std::string that has one parameter of type int. So the compiler issues the error.

[vlad from moscow]

Also it is not clear what you are trying to do. The function you defined does not use the argument passed to it.

[Ardeshir81]

Thanks!
I really appreciate it ;
and forget about the function , it does something important , I just changed it for this forum so that the good people like you don't have problem answering me :))))
Thanks again !

[vlad from moscow]

You can do what you want the following way provided that your compiler supports std::initializer_list


cout << onetwo ( { input [0], input [1] } ) ;