算子==不匹配std向量

Question

我被这个错误困住了：

从/cvmfs/cluster/gcc/gcc-4.8.3/include/c++/4.8.3/algorithm:62:0，到/cluster/compwa_externals/boost_1_55_0/include/boost/move/algorithm.hpp:23，的文件中包含的gcc.compile.c++ gcc.compile.c++从/cluster/compwa_externals/boost_1_55_0/include/boost/move/move.hpp:24，到/cluster/compwa_externals/boost_1_55_0/include/boost/unordered/detail/util.hpp:19，从/cluster/compwa_externals/boost_1_55_0/include/boost/unordered/detail/buckets.hpp:14，从/cluster/compwa_externals/boost_1_55_0/include/boost/unordered/detail/table.hpp:10，到/cluster/compwa_externals/boost_1_55_0/include/boost/unordered/detail/equivalent.hpp:14，从/cluster/compwa_externals/boost_1_55_0/include/boost/unordered/unordered_set.hpp:17，从/cluster/compwa_externals/boost_1_55_0/include/boost/unordered_set.hpp:16，到/cluster/compwa_externals/boost_1_55_0/include/boost/graph/adjacency_list.hpp:21，从Physics/HelicityAmplitude/HelicityDecayTree.hpp:17，从Physics/HelicityAmplitude/HelicityDecayTree.cpp:12： /cvmfs/cluster/gcc/gcc-4.8.3/include/c++/4.8.3/bits/stl_algo.h:在“_RandomAccessIterator std：：__find”( _RandomAccessIterator，_RandomAccessIterator，const _Tp&，std::random_access_iterator_tag)的实例化中使用_RandomAccessIterator= __gnu_cxx::__normal_iterator >；_Tp =HelicityFormalism：：粒子克利尔状态： /cvmfs/cluster/gcc/gcc-4.8.3/include/c++/4.8.3/bits/stl_algo.h:4441:45:需要从‘_IIter std::find(_IIter，_IIter，const _Tp&)到_IIter= __gnu_cxx::__normal_iterato r >；_Tp =HelicityFormalism：：ParticleState’从这里需要 /cvmfs/cluster/gcc/gcc-4.8.3/include/c++/4.8.3/bits/stl_algo.h:166:17:错误:与‘operator==’不匹配(操作数类型为‘HelicityFormalism：：ParticleState’和‘const：：ParticleState’) if (*__first == __val)

我看到他要求对ParticleState进行比较。不过，我真的不明白他为什么要这个比较。我的相关代码如下：

类的标题：

class HelicityDecayTree {
  boost::adjacency_list<> decay_tree_;
  std::vector<ParticleState> particles_;

public:
  void createDecay(const ParticleState &mother,
  const ParticleStatePair &daughters);
}

以及该成员函数的来源：

void HelicityDecayTree::createDecay(const ParticleState &mother,
    const ParticleStatePair &daughters) {
  // add particles to the list
  unsigned int mother_vector_index;
  unsigned int daughter1_vector_index;
  unsigned int daughter2_vector_index;

  if (std::find(particles_.begin(), particles_.end(), mother)
      == particles_.end()) {
    mother_vector_index = particles_.size();
    particles_.push_back(mother);
  }
  else {
    mother_vector_index = std::distance(particles_.begin(),
        std::find(particles_.begin(), particles_.end(), mother));
  }
  if (std::find(particles_.begin(), particles_.end(), daughters.first)
      == particles_.end()) {
    daughter1_vector_index = particles_.size();
    particles_.push_back(daughters.first);
  }
  else {
    daughter1_vector_index = std::distance(particles_.begin(),
        std::find(particles_.begin(), particles_.end(), daughters.first));
  }
  if (std::find(particles_.begin(), particles_.end(), daughters.second)
      == particles_.end()) {
    daughter2_vector_index = particles_.size();
    particles_.push_back(daughters.second);
  }
  else {
    daughter2_vector_index = std::distance(particles_.begin(),
        std::find(particles_.begin(), particles_.end(), daughters.second));
  }

  // then make the correct inserts into the vector and link appropriately
  boost::add_edge(mother_vector_index, daughter1_vector_index, decay_tree_);
  boost::add_edge(mother_vector_index, daughter2_vector_index, decay_tree_);
}

和ParticleState结构：

struct ParticleState {
  int particle_id_;
  std::string name_;
  Spin J_;
  Spin M_;
};

他应该为两个const ParticleStates合成operator==，但出于某种原因，查找方法是要求一个非const版本的1参数.

提前决定，史蒂夫

Answer 1

好吧，我忘了编译器不会合成operator==。所以我只是失踪了

bool operator==(const ParticleState &rhs) const {
  ...
}