Ok ... Ich habe diese Struktur und Vergleich funktions-std :: sort und binäre '=' Operator Problem mit einem C++ struct
struct Edge
{
char point1;
char point2;
int weight;
bool operator<(const Edge& rhs) const
{
return(weight < rhs.weight);
}
}; //end Edge
bool compareEdge(const Edge& lhs, const Edge& rhs)
{
return(lhs.weight < rhs.weight);
}
ich einen Vektor haben erklärt, wie ...
vector<Edge> edges;
Schließlich versuche ich mit dem < Operator zu sortieren ...
sort(edges.begin(), edges.end());
und ich erhalte die folgenden Fehler in Visual Studio 2005 ...
------ Build started: Project: RadakovichLab6, Configuration: Debug Win32 ------ Compiling... graph.cpp c:\program files\microsoft visual studio 8\vc\include\algorithm(2981) : error C2678: binary '=' : no operator found which takes a left-hand operand of type 'const Edge' (or there is no acceptable conversion)
c:\documents and settings\jake\my documents\visual studio 2005\projects\radakovichlab6\graph.h(25): could be 'Edge &Edge::operator =(const Edge &)'
while trying to match the argument list '(const Edge, Edge)'
c:\program files\microsoft visual studio 8\vc\include\algorithm(2997) : see reference to function template instantiation 'void std::_Insertion_sort1<_BidIt,Edge>(_BidIt,_BidIt,_Ty*)' being compiled
with
[
_BidIt=std::_Vector_const_iterator<Edge,std::allocator<Edge>>,
_Ty=Edge
]
c:\program files\microsoft visual studio 8\vc\include\algorithm(3105) : see reference to function template instantiation 'void std::_Insertion_sort<_RanIt>(_BidIt,_BidIt)' being compiled
with
[
_RanIt=std::_Vector_const_iterator<Edge,std::allocator<Edge>>,
_BidIt=std::_Vector_const_iterator<Edge,std::allocator<Edge>>
]
c:\program files\microsoft visual studio 8\vc\include\algorithm(3112) : see reference to function template instantiation 'void std::_Sort<std::_Vector_const_iterator<_Ty,_Alloc>,__w64 int>(_RanIt,_RanIt,_Diff)' being compiled
with
[
_Ty=Edge,
_Alloc=std::allocator<Edge>,
_RanIt=std::_Vector_const_iterator<Edge,std::allocator<Edge>>,
_Diff=__w64 int
]
c:\documents and settings\jake\my documents\visual studio 2005\projects\radakovichlab6\graph.cpp(107) : see reference to function template instantiation 'void std::sort<std::_Vector_const_iterator<_Ty,_Alloc>>(_RanIt,_RanIt)' being compiled
with
[
_Ty=Edge,
_Alloc=std::allocator<Edge>,
_RanIt=std::_Vector_const_iterator<Edge,std::allocator<Edge>>
] c:\program files\microsoft visual studio 8\vc\include\algorithm(2988) : error C2678: binary '=' : no operator found which takes a left-hand operand of type 'const Edge' (or there is no acceptable conversion)
c:\documents and settings\jake\my documents\visual studio 2005\projects\radakovichlab6\graph.h(25): could be 'Edge &Edge::operator =(const Edge &)'
while trying to match the argument list '(const Edge, const Edge)' c:\program files\microsoft visual studio 8\vc\include\algorithm(2989) : error C2678: binary '=' : no operator found which takes a left-hand operand of type 'const Edge' (or there is no acceptable conversion)
c:\documents and settings\jake\my documents\visual studio 2005\projects\radakovichlab6\graph.h(25): could be 'Edge &Edge::operator =(const Edge &)'
while trying to match the argument list '(const Edge, Edge)' Generating Code... Compiling... main.cpp Generating Code... Build log was saved at "file://c:\Documents and Settings\Jake\My Documents\Visual Studio 2005\Projects\RadakovichLab6\Debug\BuildLog.htm" RadakovichLab6 - 3 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
Die Frage ist in der ersten Zeile des Fehlers. Ich bekomme diesen Fehler, ob ich den überladenen Operator < verwende oder die Vergleichsfunktion an die Funktion std :: sort übergeben. Der Standard-Zuweisungsoperator der Edge-Struktur sollte ausreichen, denke ich, weil es keinen dynamisch zugewiesenen Speicher gibt. Wenn jemand eine Einsicht hat, wäre ich dankbar.
vollständige Code ...
#include <list>
#include <map>
#include <queue>
#include <vector>
#include <algorithm>
#include <iostream>
using namespace std;
//the Edge and aGraph together represent the adjacency list
//representation of a graph.
struct Edge
{
char point1; //this represents the endpoint of an edge
char point2;
int weight; //this is the weight of the edge
bool operator<(const Edge& rhs) const
{
return(weight < rhs.weight);
}
}; //end Edge
class Graph
{
public:
//Default constructor
Graph();
//This method inputs an edge into a graph.
void inputEdge(char pointA, char pointB, int wt)
{
//used to input the edges of the graph
Edge anEdge;
//prepare for insertion into list
anEdge.point1 = pointA;
anEdge.point2 = pointB;
anEdge.weight = wt;
edges.push_back(anEdge);
//insert edge into the adjacency list.
aGraph[pointA].push_front(pointB);
//insert the opposite direction into the
//adjacency list.
aGraph[pointB].push_front(pointA)
}
//This...
void bfs();
//This prints a graph and is used only for debugging purposes.
void printGraph() const
{
list<char>::const_iterator listIter;
map<char, list<char>>::const_iterator mapIter;
for(mapIter = aGraph.begin();
mapIter != aGraph.end();
mapIter++)
{
for(listIter = mapIter->second.begin();
listIter != mapIter->second.end();
listIter++)
{
cout << mapIter->first << " " << *listIter << endl;
} //end for
} //end for
sort(edges.begin(), edges.end());
vector<Edge>::const_iterator vectIt;
for(vectIt = edges.begin();
vectIt != edges.end();
vectIt++)
{
cout << vectIt->point1 << " " << vectIt->point2 << " " << vectIt->weight << endl;
} //end for
} //end printGraph
private:
//This is the adjacency list
map<char, list<char>> aGraph;
//This is a list of edges and their weights.
vector<Edge> edges;
}; //end Graph
int main()
{
Graph myGraph;
myGraph.inputEdge('O', 'A', 2);
myGraph.inputEdge('O', 'B', 5);
myGraph.inputEdge('O', 'C', 4);
myGraph.inputEdge('A', 'B', 2);
myGraph.inputEdge('A', 'D', 7);
myGraph.inputEdge('B', 'D', 4);
myGraph.inputEdge('B', 'E', 3);
myGraph.inputEdge('C', 'B', 1);
myGraph.inputEdge('C', 'E', 4);
myGraph.inputEdge('E', 'D', 1);
myGraph.inputEdge('D', 'T', 5);
myGraph.inputEdge('E', 'T', 7);
myGraph.inputEdge('G', 'Z', 8);
myGraph.printGraph();
cout << endl << endl;
system("PAUSE");
return 0;
} //end main
Hier ist der Code ...
Wir müssen die Fehlermeldungen nicht sehen, wir müssen den Code sehen, der sie verursacht hat. –