how to add a int to a char[] in c/c++

Question

i have a code like this:

int i = 123;
char myString[100];
strcpy(myString, "my text");

and how i want to add the 123 after "my text". how to do this in c/c++?

at the end myString sould be my test123

C and C++ are two different languages. They way you would do this in C is completely different from how you'd do it in C++. — Adam Rosenfield, Sep 27 '12 at 19:55
If C++, have a look at this: http://stackoverflow.com/questions/5590381/easiest-way-to-convert-int-to-string-in-c — chris, Sep 27 '12 at 19:56
http://stackoverflow.com/questions/347132/append-an-int-to-char — Xiphos, Sep 27 '12 at 19:56

score 8 · Answer 1 · answered Sep 27 '12 at 19:54

8

In C++:

std::stringstream ss;
ss << "my text" << i;
std::string resultingString = ss.str();

There's no such thing as C/C++.

answered Sep 27 '12 at 19:54

Luchian Grigore

score 7 · Answer 2 · answered Sep 27 '12 at 19:55

7

In C++11:

std::string result = "my text" + std::to_string(i);

answered Sep 27 '12 at 19:55

Pete Becker

score 6 · Accepted Answer · 2012-09-27T20:05:15.373

6

(To complement Luchian's answer)

In C:

char myString[128];
int i = 123;
snprintf(myString, sizeof(myString), "My Text %d", i);

edited Sep 27 '12 at 20:05

answered Sep 27 '12 at 19:55

2

Note: this only works if `myString` is an array. If it's a pointer instead, you must keep track of the length of the pointed-to buffer and pass that in as the second argument of `snprintf`, since `sizeof(pointer)` is not what you want (it's typically 4 or 8 bytes). – Adam Rosenfield Sep 27 '12 at 20:02
Yeah, I was just adding clarification in case anyone came by and decided to copy+paste the code without fully understanding it. – Adam Rosenfield Sep 27 '12 at 20:57
@AdamRosenfield valid reason, absolutely. (NO ONE should copy-paste code without understanding it though, right?) – Sep 27 '12 at 21:03

score 4 · Answer 4 · answered Sep 27 '12 at 19:54

4

Assuming mystring is large enough, which it is in this example:

sprintf( myString, "my text%d", 123 );

answered Sep 27 '12 at 19:54

Mark Stevens

1

Sorry, man, but -1 for not using snprintf(). You should really be secure. – Sep 27 '12 at 19:56

score 0 · Answer 5 · answered Sep 27 '12 at 20:05

0

With the Qt QString object in C++:

std::cout << QString("my text %1").arg(123456);

answered Sep 27 '12 at 20:05

fonZ

5 Answers5