我在我的 qt 项目 m 中包含了“Edge_collapse_recorder.h”,我想在折叠过程中打印一些值,但是当我取消注释 std::cout << "collapse edge "<< profile 时它显示以下错误.v0_v1() << ""<<<< profile.v0() << ""<< profile.v1() << std::endl; 行:
../CM2/edge_collapse_recorder.h:102:37: error: no match for ‘operator<<’ (operand types are ‘std::basic_ostream<char>’ and ‘const halfedge_descriptor’ {aka ‘const CGAL::internal::CC_iterator<CGAL::Compact_container<CGAL::Dart<2, CGAL::CMap_linear_cell_complex_storage_1<2, 3, CGAL::Linear_cell_complex_traits<3, CGAL::Simple_cartesian<double> >, CGAL::Linear_cell_complex_bgl_min_items, std::allocator<int> >, CGAL::Void, CGAL::Boolean_tag<true> >, std::allocator<CGAL::Dart<2, CGAL::CMap_linear_cell_complex_storage_1<2, 3, CGAL::Linear_cell_complex_traits<3, CGAL::Simple_cartesian<double> >, CGAL::Linear_cell_complex_bgl_min_items, std::allocator<int> >, CGAL::Void, CGAL::Boolean_tag<true> > >, CGAL::Default, CGAL::Default>, false>’})
std::cout << "collapse edge " << profile.v0_v1() << " " << << profile.v0() << " " << profile.v1() << std::endl;
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
我搜索了这个问题,发现我必须重载 << 运算符,然后我将以下内容添加到 onCollapssing 方法:
std::ostream& operator<<(std::ostream& os, const Edge_collapse_recorder& t) {
os << << "collapse edge " << t.v0_v1() << " " << << t.v0() << " " << t.v1();
return os;
}
但它显示以下错误: 在‘{’token”之前不允许函数定义”
void OnCollapsing(Profile const& profile
,boost::optional<Point_3> placement
)
{
visitor.OnCollapsing(profile,placement);
if ( placement ){
std::ostream& operator<<(std::ostream& os, const Edge_collapse_recorder& t) {
os << << "collapse edge " << t.v0_v1() << " " << << t.v0() << " " << t.v1();
return os;
}
Record record;
record.v0 = profile.v0();
record.v1 = profile.v1();
record.p0 = profile.p0();
record.p1 = profile.p1();
halfedge_descriptor hd = profile.v0_v1();
record.oppa = (! is_border(hd,recorder.sm))
? target(next(hd, recorder.sm),recorder.sm)
: boost::graph_traits<LCC>::null_vertex();
record.oppb = (! is_border(opposite(hd, recorder.sm),recorder.sm))
? target(next(opposite(hd, recorder.sm), recorder.sm),recorder.sm)
: boost::graph_traits<LCC>::null_vertex();
recorder.records.push_back(record);
}
}
最佳答案
那条被注释掉的行永远不会编译。它有两个连续的 <<
运营商。
至于报错信息,你在定义函数
std::ostream& operator<<(std::ostream& os, const Edge_collapse_recorder& t)
(而不只是声明它)在另一个函数中。 C++
中不允许嵌套函数定义.做你想做的事(我不确定这是否是个好主意),将函数定义放在 OnCollapsing
之前。功能。
关于c++ - 此处不允许在 ‘{’ token 之前定义函数”,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/55086798/