Thread: Join string and int.

Hi,

It looks like you took a statement like this:

Code:

cout<<"value of x is " << x << " value of y is " << y;

and substituted message= in place of cout<<. What on earth did you read about C++ that made you think that cout<< and message= are equivalent?

The fact that you are asking such a question indicates you probably wouldn't understand the somewhat complex method you have to use for joining a string and an int in C++, but if you are interested look up stringstreams.

'message' is a char variable.

Where x is 5, and y were 3, I'd like the string to read

value of x is 5 value of y is 3.

I assumed that << would join variables together. In php, you would write something like:

Code:

echo "value of x is " . $x . " value of y ix " . $y;

Might I have some example code equivilent to that?

>>>> EDIT

I've solved the issue, is this a hacky solution?

Code:

	int x = 5, y = 3;
	char message [50];

	sprintf( message, "x is %i , y is %i ", x, y);

operator << can take string and numeric right-hand arguments, but there must be a class on the left-hand side performing the operation (whatever that operation may be). In the example of

Code:

cout << "the value of x is " << x;

it would be equivalent to writing

Code:

cout.operator<<("the value of x is ").operator<<(x);

Don't confuse that dot with a PHP dot for concatenation. cout's operator<< implementation returns what you should think of as cout itself. So really that translation would also be equivalent to saying

Code:

cout.operator<<("the value of x is");
cout.operator<<(x);

Since you are posting in the c++ thread, a grand solution would be to take advantage of the ostringstream class (#include <sstream>). You can search the board for examples.
For a more primitive solution, use sprintf().

stringstream example / stringstream article