Question

尝试使用类似下面的内容与char数组，但它不能编译。但是short []的例子很好用。知道为什么吗？：）

char someChars[] = {'s','h','e','r','r','y'};
    BOOST_FOREACH(char& currentChar, someChars)
    {

    }


short array_short[] = { 1, 2, 3 };
    BOOST_FOREACH( short & i, array_short )
    {
        ++i;
    }

Answer 1

如果您转到引发编译错误的<boost/foreach.hpp>行，您会看到以下注释：

// **** READ THIS IF YOUR COMPILE BREAKS HERE ****
//
// There is an ambiguity about how to iterate over arrays of char and wchar_t. 
// Should the last array element be treated as a null terminator to be skipped, or
// is it just like any other element in the array? To fix the problem, you must
// say which behavior you want.
//
// To treat the container as a null-terminated string, merely cast it to a
// char const *, as in BOOST_FOREACH( char ch, (char const *)"hello" ) ...
//
// To treat the container as an array, use boost::as_array() in <boost/range/as_array.hpp>,
// as in BOOST_FOREACH( char ch, boost::as_array("hello") ) ...

使用注释中显示的boost::as_array(someChars)可以修复编译错误。

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