Question

So I’ve been going back and forth from C++, C# and Java lately and well writing some C++ code I did something like this.

string LongString = "Long String";

char firstChar = LongString.at(0);

And then tried using a method that looks like this,

void MethodA(string str)
{    
//some code    
cout << str;    
//some more code }

Here’s how I implemented it.

MethodA("1. "+ firstChar );

though perfectly valid in C# and Java this did something weird in C++.

I expected something like

//1. L

but it gave me part of some other string literal later in the program.

what did I actually do?

I should note I’ve fixed the mistake so that it prints what I expect but I’m really interested in what I mistakenly did.

Thanks ahead of time.

Answer 1

C++ does not define addition on string literals as concatenation. Instead, a string literal decays to a pointer to its first element; a single character is interpreted as a numeric value so the result is a pointer offset from one location in the program’s read-only memory segment to another.

To get addition as concatenation, use std::string:

MethodA(std::string() + "1. " + firstChar);