Page 22 Source Code

golfer43 · April 21st, 2012, 08:08 PM

The little piece of code on page 22 does not seem to work in VC++11 but produces no errors in VC++10. In VC++11, it is saying that the i defined with the auto needs an initializer. VC++10 does not produce that error.

Marc Gregoire · April 22nd, 2012, 03:52 AM

There is a small misprint, which should appear on the books' errata page, but it's not there yet.

I just tried the following code in Visual C++ 11 Beta and it works correctly:

Code:

#include <iostream>
#include <array>

using namespace std;

int main()
{
	array<int, 3> arr = {9, 8, 7};
	cout << "Array size = " << arr.size() << endl;
	for (auto i : arr)
		cout << i << endl;

	return 0;
}

Is this piece of code giving an error when you try it?

golfer43 · April 22nd, 2012, 12:25 PM

Hi Marc,
This is truly odd. When I Build it, it says down at the bottom left that it succeeded. However, on the line of the 'for loop' there are 3 small seperate squiggly lines. One under the 'i', one under the colon, and one under the right parenthesis. Here are the error messages I'm getting at the bottom. (Sorry if their not formatted correctly.)

Quote:

1 IntelliSense: cannot deduce 'auto' type (initializer required) c:\Users\Bob\Documents\Visual Studio 11\Projects\test\test\Source.cpp 10 12 test
2 IntelliSense: expected a ';' c:\Users\Bob\Documents\Visual Studio 11\Projects\test\test\Source.cpp 10 14 test
3 IntelliSense: expected an expression c:\Users\Bob\Documents\Visual Studio 11\Projects\test\test\Source.cpp 10 19 test

Marc Gregoire · April 22nd, 2012, 12:41 PM

That's the IntelliSense.
IntelliSense still has a problem with correctly parsing the range-based for loop, and thus shows you red squiggly lines.
However, the real VC++ compiler understands range-based for loops perfectly fine, as you can see in your case where it says "succeeded". After compiling, just try to execute your program, and you'll see it's working correctly, even with the red squiggles.
This is a know issue with IntelliSense, and Microsoft is working on it.