C++ Lambda Function for BFS Traversal
Using the two functions below, how could I use a lambda function to BFS Traverse through a Graph of Thing's called x
i.e. Graph<Thing> x
which involves sending the display function to the bfsTraverse function so that the information in each Thing can be displayed.
void display(const Thing& c)
{
cout<<left<<setw(3)<<c.getKey()<<" "<<left<<setw(2)<<c.getLabel()<<endl;
}
template <typename E>
void Graph<E>::bfsTraverse(FuncType func)
{
/* some code not necessary to describe */
}
So basically, I just need to understand how to use a lambda function to tie these together here.
c++ algorithm lambda graph-theory breadth-first-search
add a comment |
Using the two functions below, how could I use a lambda function to BFS Traverse through a Graph of Thing's called x
i.e. Graph<Thing> x
which involves sending the display function to the bfsTraverse function so that the information in each Thing can be displayed.
void display(const Thing& c)
{
cout<<left<<setw(3)<<c.getKey()<<" "<<left<<setw(2)<<c.getLabel()<<endl;
}
template <typename E>
void Graph<E>::bfsTraverse(FuncType func)
{
/* some code not necessary to describe */
}
So basically, I just need to understand how to use a lambda function to tie these together here.
c++ algorithm lambda graph-theory breadth-first-search
add a comment |
Using the two functions below, how could I use a lambda function to BFS Traverse through a Graph of Thing's called x
i.e. Graph<Thing> x
which involves sending the display function to the bfsTraverse function so that the information in each Thing can be displayed.
void display(const Thing& c)
{
cout<<left<<setw(3)<<c.getKey()<<" "<<left<<setw(2)<<c.getLabel()<<endl;
}
template <typename E>
void Graph<E>::bfsTraverse(FuncType func)
{
/* some code not necessary to describe */
}
So basically, I just need to understand how to use a lambda function to tie these together here.
c++ algorithm lambda graph-theory breadth-first-search
Using the two functions below, how could I use a lambda function to BFS Traverse through a Graph of Thing's called x
i.e. Graph<Thing> x
which involves sending the display function to the bfsTraverse function so that the information in each Thing can be displayed.
void display(const Thing& c)
{
cout<<left<<setw(3)<<c.getKey()<<" "<<left<<setw(2)<<c.getLabel()<<endl;
}
template <typename E>
void Graph<E>::bfsTraverse(FuncType func)
{
/* some code not necessary to describe */
}
So basically, I just need to understand how to use a lambda function to tie these together here.
c++ algorithm lambda graph-theory breadth-first-search
c++ algorithm lambda graph-theory breadth-first-search
edited Nov 22 '18 at 1:58
Dominique Fortin
1,665817
1,665817
asked Mar 21 '17 at 2:46
RoryHectorRoryHector
548
548
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add a comment |
1 Answer
1
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It pretty straightforward. For example, let;s print values of vector using lambda:
#include <algorithm>
#include <vector>
#include <iostream>
int main (int argc, char* argv) {
std::vector <int> data{1,2,3,4};
std::for_each (data.begin (), data.end (), (const int val) { std::cout << val << std::endl;});
return 0;
}
last argument (...) is the lambda.
A function, which accepts lambdas, might look like this:
template <typename E, typename FuncType>
void Graph<E>::bfsTraverse (FuncType func)
{
/* some code not necessary to describe */
}
UPDATE
In case of a graph you should do the following. Your graph's implementation should have a method to access vertices: it might be 'getRoot', 'getSource', 'getAllNodes', it's implementation defined. I'll stick with 'getRoot'. Each vertex/node should have a method like 'getAdjacentVertices', 'getChildren', whatever. Combining all together:
template <typename E, typename FuncType>
void Graph<E>::bfsTraverse (FuncType func)
{
std::queue<Node> q;
auto&& root = getRoot ();
q.push (root);
while (not q.empty ()) {
auto&& current = q.front ();
q.pop ();
func (current);
auto&& adjacent = current.getAdjacent ();
for (auto&& a: adjacent) {
q.push (a);
}
}
Be aware, that I deliberately omit keeping list of visited nodes and other things. But idea itself stays the same. Now you can call this function as follows:
Graph<E> g;
g.bfsTraverse ( (const Node& n) {
std::cout << n.to_str () << std::endl;
}
);
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
It pretty straightforward. For example, let;s print values of vector using lambda:
#include <algorithm>
#include <vector>
#include <iostream>
int main (int argc, char* argv) {
std::vector <int> data{1,2,3,4};
std::for_each (data.begin (), data.end (), (const int val) { std::cout << val << std::endl;});
return 0;
}
last argument (...) is the lambda.
A function, which accepts lambdas, might look like this:
template <typename E, typename FuncType>
void Graph<E>::bfsTraverse (FuncType func)
{
/* some code not necessary to describe */
}
UPDATE
In case of a graph you should do the following. Your graph's implementation should have a method to access vertices: it might be 'getRoot', 'getSource', 'getAllNodes', it's implementation defined. I'll stick with 'getRoot'. Each vertex/node should have a method like 'getAdjacentVertices', 'getChildren', whatever. Combining all together:
template <typename E, typename FuncType>
void Graph<E>::bfsTraverse (FuncType func)
{
std::queue<Node> q;
auto&& root = getRoot ();
q.push (root);
while (not q.empty ()) {
auto&& current = q.front ();
q.pop ();
func (current);
auto&& adjacent = current.getAdjacent ();
for (auto&& a: adjacent) {
q.push (a);
}
}
Be aware, that I deliberately omit keeping list of visited nodes and other things. But idea itself stays the same. Now you can call this function as follows:
Graph<E> g;
g.bfsTraverse ( (const Node& n) {
std::cout << n.to_str () << std::endl;
}
);
add a comment |
It pretty straightforward. For example, let;s print values of vector using lambda:
#include <algorithm>
#include <vector>
#include <iostream>
int main (int argc, char* argv) {
std::vector <int> data{1,2,3,4};
std::for_each (data.begin (), data.end (), (const int val) { std::cout << val << std::endl;});
return 0;
}
last argument (...) is the lambda.
A function, which accepts lambdas, might look like this:
template <typename E, typename FuncType>
void Graph<E>::bfsTraverse (FuncType func)
{
/* some code not necessary to describe */
}
UPDATE
In case of a graph you should do the following. Your graph's implementation should have a method to access vertices: it might be 'getRoot', 'getSource', 'getAllNodes', it's implementation defined. I'll stick with 'getRoot'. Each vertex/node should have a method like 'getAdjacentVertices', 'getChildren', whatever. Combining all together:
template <typename E, typename FuncType>
void Graph<E>::bfsTraverse (FuncType func)
{
std::queue<Node> q;
auto&& root = getRoot ();
q.push (root);
while (not q.empty ()) {
auto&& current = q.front ();
q.pop ();
func (current);
auto&& adjacent = current.getAdjacent ();
for (auto&& a: adjacent) {
q.push (a);
}
}
Be aware, that I deliberately omit keeping list of visited nodes and other things. But idea itself stays the same. Now you can call this function as follows:
Graph<E> g;
g.bfsTraverse ( (const Node& n) {
std::cout << n.to_str () << std::endl;
}
);
add a comment |
It pretty straightforward. For example, let;s print values of vector using lambda:
#include <algorithm>
#include <vector>
#include <iostream>
int main (int argc, char* argv) {
std::vector <int> data{1,2,3,4};
std::for_each (data.begin (), data.end (), (const int val) { std::cout << val << std::endl;});
return 0;
}
last argument (...) is the lambda.
A function, which accepts lambdas, might look like this:
template <typename E, typename FuncType>
void Graph<E>::bfsTraverse (FuncType func)
{
/* some code not necessary to describe */
}
UPDATE
In case of a graph you should do the following. Your graph's implementation should have a method to access vertices: it might be 'getRoot', 'getSource', 'getAllNodes', it's implementation defined. I'll stick with 'getRoot'. Each vertex/node should have a method like 'getAdjacentVertices', 'getChildren', whatever. Combining all together:
template <typename E, typename FuncType>
void Graph<E>::bfsTraverse (FuncType func)
{
std::queue<Node> q;
auto&& root = getRoot ();
q.push (root);
while (not q.empty ()) {
auto&& current = q.front ();
q.pop ();
func (current);
auto&& adjacent = current.getAdjacent ();
for (auto&& a: adjacent) {
q.push (a);
}
}
Be aware, that I deliberately omit keeping list of visited nodes and other things. But idea itself stays the same. Now you can call this function as follows:
Graph<E> g;
g.bfsTraverse ( (const Node& n) {
std::cout << n.to_str () << std::endl;
}
);
It pretty straightforward. For example, let;s print values of vector using lambda:
#include <algorithm>
#include <vector>
#include <iostream>
int main (int argc, char* argv) {
std::vector <int> data{1,2,3,4};
std::for_each (data.begin (), data.end (), (const int val) { std::cout << val << std::endl;});
return 0;
}
last argument (...) is the lambda.
A function, which accepts lambdas, might look like this:
template <typename E, typename FuncType>
void Graph<E>::bfsTraverse (FuncType func)
{
/* some code not necessary to describe */
}
UPDATE
In case of a graph you should do the following. Your graph's implementation should have a method to access vertices: it might be 'getRoot', 'getSource', 'getAllNodes', it's implementation defined. I'll stick with 'getRoot'. Each vertex/node should have a method like 'getAdjacentVertices', 'getChildren', whatever. Combining all together:
template <typename E, typename FuncType>
void Graph<E>::bfsTraverse (FuncType func)
{
std::queue<Node> q;
auto&& root = getRoot ();
q.push (root);
while (not q.empty ()) {
auto&& current = q.front ();
q.pop ();
func (current);
auto&& adjacent = current.getAdjacent ();
for (auto&& a: adjacent) {
q.push (a);
}
}
Be aware, that I deliberately omit keeping list of visited nodes and other things. But idea itself stays the same. Now you can call this function as follows:
Graph<E> g;
g.bfsTraverse ( (const Node& n) {
std::cout << n.to_str () << std::endl;
}
);
edited Mar 22 '17 at 0:55
answered Mar 21 '17 at 3:19
CaptainTrunkyCaptainTrunky
95821019
95821019
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