For each loop in Native C++

　　今天发现 for each 语法居然可以直接编译通过，之前还以为只有开了/clr才可以支持。查了一下资料发现ms从vs2005就已经支持了。虽然不符合标准不过用着确实方便啊，必须记录一下。

　　具体看这里，已经有人介绍过了。http://www.codeproject.com/Tips/76166/For-each-loop-in-Native-C

Since Visual Studio 2005, native C++ has had a ‘for each’ loop construct, like C# or Java. Unfortunately it is restricted to collections from the STL library, such as vector. However, it does mean you can write very neat code to iterate through such a collection:



vector<int> data(3);
data[0] = 10;
data[1] = 20;
data[2] = 30;

//instead of this
int total = 0;
for (vector<int>::iterator vi = data.begin(); vi != data.end(); vi++)
{
    int i = *vi;
    total += i;
}
cout << "total: " << total << endl;

// do this:
total = 0;
for each( const int i in data )
    total += i;
cout << "total: " << total << endl;



Now we just need that making part of the C++ standard! If you are writing standard compliant code you will have to use the for_each function [^].