Question

我遇到了Boost C ++单元测试框架的问题。这是 someclass.h文件

class someclass {
   public:
      someclass(int a_x, int b_x);
      someclass();

      friend bool operator<(someclass& lhs, someclass& rhs);
      friend ostream& operator<<(ostream& stream, const someclass& sa);

   private:
      int a;
      int b;
};

这是someclass.cpp文件

#include <iostream>
#include <ostream>
#include <vector>
#include <tuple>

using std::cout;
using std::endl;
using std::vector;
using std::ostream;

#include "someclass.h"

someclass::someclass(int a_x, int b_x)
:a(a_x), b(b_x)
{
}

//-------------------------------------------------------

someclass::someclass()
{
}

//-------------------------------------------------------

bool operator<(someclass& lhs, someclass& rhs)
{
   return std::tie(lhs.a, lhs.b) < std::tie(rhs.a, rhs.b);
}

//-------------------------------------------------------
ostream& operator<<(ostream& stream, const someclass& rhs)
{
   stream << "(" << rhs.a << "," << rhs.b << ")";
   return stream;
}

以下是测试它的程序：

#define BOOST_TEST_MODULE test_someclass
#define BOOST_TEST_DYN_LINK
#include <boost/test/unit_test.hpp>

#include <ostream>

using std::ostream;

#include "someclass.h"

BOOST_AUTO_TEST_CASE( someclass_lt )
{
   someclass sa1(1,4);
   someclass sa2(1,5);
   someclass sa3(2,3);
   someclass sa4(2,4);
   someclass sa5(2,5);

   BOOST_TEST( sa1 < sa2 );
   BOOST_TEST( !(sa2 < sa1) );
   BOOST_TEST( sa1 < sa3 );
   BOOST_TEST( sa1 < sa4 );
   BOOST_TEST( sa1 < sa5 );
}

someclass.cpp文件本身编译得很好，但是当我尝试编译时整个事情我得到了一大堆错误信息，部分是

In file included from testsomeclass.cpp:9:0:
someclass.h:6:19: note: bool operator<(someclass&, someclass&)
       friend bool operator<(someclass& lhs, someclass& rhs);
                   ^
someclass.h:6:19: note:   no known conversion for argument 1 from ‘someclass’ to ‘someclass&’

我已经尝试过每一种我能想到的方法来纠正这一点，但无济于事。我也在stackoverflow.com和许多其他网站上搜索，但无济于事。有人可以告诉我什么是错的，并且确切地说如何修复它？感谢。

布鲁斯

Answer 1

你应该使用正确的constness：

friend bool operator<(const someclass& lhs, const someclass& rhs);

C ++ boost测试无法测试运算符＆lt;

1 个答案: