How to fix binary operators errors? - c++

Question

I have to write code that represent the graph using an adjacency list. I tried setting up my code to use a std::list but now that gives me errors saying
Error C2679 binary '=': no operator found which takes a right-hand operand of type 'int' (or there is no acceptable conversion) on multiple lines of my code. I'm confused on how I get my code to use an adjacency list without having all these issues.
#include "GraphInterface.h"
#include <string>
#include <fstream>
#include <iostream>
#include <vector>
#include<list>
#ifndef GRAPH_TWO
#define GRAPH_TWO
template<class LabelType>
class GraphTwo : public GraphInterface<LabelType>
{
private:
// Define maximum number of nodes
static const int size = 10;
std::list <int> adj[size][size];
std::list<bool>visited[size];
public:
GraphTwo();
// Get the number of vertices
int getNumVertices() const;
// Get the number of the edges
int getNumEdges() const;
// Creates an undirected edge in this graph between two vertices
// that have the given labels.If such vertices do not exist, creates
// themand adds them to the graph before creating the edge
bool add(LabelType start, LabelType end, int edgeWeight);
// Removes an edge from this graph. If a vertex has no other edges,
// it is removed from the graph since this is a connected graph.
bool remove(LabelType start, LabelType end);
// Gets the weight of an edge in this graph.
int getEdgeWeight(LabelType start, LabelType end) const;
// Performs a depth - first search of this graph beginning at the given
// vertex and calls a given function once for each vertex visited.
void depthFirstTraversal(LabelType start, void visit(LabelType&));
// Performs a breadth - first search of this graph beginning at the given
// vertex and calls a given function once for each vertex visited.
void breadthFirstTraversal(LabelType start, void visit(LabelType&));
};
template<class LabelType>
GraphTwo<LabelType>::GraphTwo()
{}
template<class LabelType>
int GraphTwo<LabelType>::getNumVertices() const
{
return size;
}
template<class LabelType>
int GraphTwo<LabelType>::getNumEdges() const
{
int edgeCount = 0;
for (int i = 0; i < size; ++i)
for (int j = 0; j < size; ++j)
if (adj[i][j] != 0)
++edgeCount;
return edgeCount / 2;
}
template<class LabelType>
bool GraphTwo<LabelType>::add(LabelType start, LabelType end, int edgeWeight)
{
adj[start][end] = edgeWeight; //error here
adj[end][start] = edgeWeight; //error here
return true;
}
template<class LabelType>
bool GraphTwo<LabelType>::remove(LabelType start, LabelType end)
{
adj[start][end] = 0; // error here
adj[end][start] = 0; // error here
return true;
}
template<class LabelType>
int GraphTwo<LabelType>::getEdgeWeight(LabelType start, LabelType end) const
{
return adj[start][end];
}
template<class LabelType>
void GraphTwo<LabelType>::depthFirstTraversal(LabelType start, void visit(LabelType&))
{
// Visit the current node
visit(start);
// Mark the current node as visited
visited[start] = true;
// For all other nodes
for (int i = 0; i < size; ++i) {
if (adj[start][i] != 0 && (!visited[i]))
depthFirstTraversal(i, visit);
}
}
template<class LabelType>
void GraphTwo<LabelType>::breadthFirstTraversal(LabelType start, void visit(LabelType&))
{
// Vector that contains the adjacent nodes
std::vector<LabelType> alist;
alist.push_back(start);
// Mark current node as visited
visited[start] = true; // error here
int check;
while (!alist.empty()) {
check = alist[0];
// Print node
visit(check);
alist.erase(alist.begin());
// Every vertex adjacent
for (int i = 0; i < size; ++i) {
if (adj[check][i] != 0 && (!visited[i])) {
// Add node to the queue
alist.push_back(i);
// Mark next node as visited
visited[i] = true; // error here
}
}
}
// Reset visited as all false
for (int i = 0; i < size; ++i)
visited[i] = false; // error here
}
#endif

Answer 1

std::list <int> adj[size][size];
This is not what you think it is. adj is an array of size arrays of size lists.
This makes adj[start][end] have type std::list<int>. The same applies to all your lists. Go find a good documentation on how to use std::list and don't try to guess the C++ syntax, learn it.