const char* concatenation

Asked 2010-01-03T14:02:57.923

152

I need to concatenate two const chars like these:

const char *one = "Hello ";
const char *two = "World";

How might I go about doing that?

I am passed these char*s from a third-party library with a C interface so I can't simply use std::string instead.

c++ c string-concatenation

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2 Answers

The C way:

char buf[100];
strcpy(buf, one);
strcat(buf, two);

The C++ way:

std::string buf(one);
buf.append(two);

The compile-time way:

#define one "hello "
#define two "world"
#define concat(first, second) first second

const char* buf = concat(one, two);

answered 2010-01-03T14:09:04.360

If you are using C++, why don't you use std::string instead of C-style strings?

std::string one="Hello";
std::string two="World";

std::string three= one+two;

If you need to pass this string to a C-function, simply pass three.c_str()

answered 2010-01-03T14:05:54.140