How to concatenate two strings in C++?

Solution 1:

First of all, don't use char* or char[N]. Use std::string, then everything else becomes so easy!

Examples,

std::string s = "Hello";
std::string greet = s + " World"; //concatenation easy!

Easy, isn't it?

Now if you need char const * for some reason, such as when you want to pass to some function, then you can do this:

some_c_api(s.c_str(), s.size());

assuming this function is declared as:

some_c_api(char const *input, size_t length);

Explore std::string yourself starting from here:

Hope that helps.

Since it's C++ why not to use std::string instead of char*? Concatenation will be trivial:

std::string str = "abc";
str += "another";

If you were programming in C, then assuming name really is a fixed-length array like you say, you have to do something like the following:

char filename[sizeof(name) + 4];
strcpy (filename, name) ;
strcat (filename, ".txt") ;
FILE* fp = fopen (filename,...

You see now why everybody recommends std::string?