Concat strings and numbers in C++?

Question

I'm trying to concat "(" + mouseX + ", " + mouseY ")". However, mouseX and mouseY are ints, so I tried using a stringstream as follows:

std::stringstream pos;
pos << "(" <<  mouseX << ", " << mouseY << ")";
_glutBitmapString(GLUT_BITMAP_HELVETICA_12, pos.str());

And it doesn't seem to work.

I get the following error:

mouse.cpp:75: error: cannot convert std::basic_string<char, std::char_traits<char>, std::allocator<char> >' toconst char*' for argument 2' tovoid _glutBitmapString(void*, const char*)'

What am I doing wrong in this basic string + integer concatenation?

Can someone who can edit this change the question to "How do I convert a stringstream to a const char*?" — jmucchiello
– jmucchiello, Commented Feb 13, 2009 at 1:48

shoosh · Accepted Answer · 2009-02-13 01:43:19Z

5

glutBitmapString() expects a char* and you're sending it a string. use .c_str() on the string like so:

_glutBitmapString(GLUT_BITMAP_HELVETICA_12, pos.str().c_str());

answered Feb 13, 2009 at 1:43

shoosh

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2 Comments

Tom Over a year ago

pedantic, but it's really expecting a "const char *". If it wanted "char *", .c_str() wouldn't work without a const_cast<char *>

Evan Teran Over a year ago

@Tom: the prototype asks for a const char *, so I am not sure why that needed to be mentioned.

Andrew Grant · Accepted Answer · 2009-02-13 01:48:14Z

3

Try

_glutBitmapString(GLUT_BITMAP_HELVETICA_12, pos.str().c_str());

edited Feb 13, 2009 at 1:48

answered Feb 13, 2009 at 1:42

Andrew Grant

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1 Comment

KingNestor Over a year ago

@Evan Teran, I think the downvote came because before the edit he had a slight mistype? I upvoted though!

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