[RESOLVED] C++ to C#

[Longbottomup]

I code a algorithm by C++(Breadth first search), i'm fluent C++, but i'm learning C#, so i don't know function or keyword between it, i need convert to learning and searching, can you help convert it, short:

#include <iostream>
#include <queue>

using namespace std;

const int maxx = 20;

void Read_input_from_user(bool grid[][maxx], int vertices)
{
    int u, v;
    for(int x = 0; x < vertices; ++x)
    {
        cout << "Enter u : \t"; 
        cin >> u;
        u--;
        cout << "Enter v : \t";
        cin >> v;
        v--;
        grid[u][v] = true;
                grid[v][u] = true;
        cout << "---------------------\n";
    }
}

void Breadth_first_search(queue<int> &Q, vector<int> &trace,
                          bool grid[][maxx], int start, int nodes)
{
    int u;
    vector<int> visited(maxx,0);
    Q.push(start);
    trace[start] = -1;
    visited[start] = 1;
    do{
        u = Q.front();
        Q.pop();
        for(int v = 0; v < nodes; ++v)
        {
            if((grid[u][v] == true) && visited[v] == 0)
            {
                Q.push(v);
                trace[v] = u;
                visited[v] = 1;
            }
        }
    }while(!Q.empty());
}

void Trace_result(vector<int> &trace, int start, int end, int nodes)
{
    cout << "From _nodes" << start + 1 << " you can visit :\n";
    for(int v = 0; v < nodes; ++v)
    {
        if(trace[v] != 0)
        {
            cout << " _nodes : " << v + 1 << " , ";
        }
    }

    cout << "\n--------------------------------------------\n";
    cout << "The path from " << start + 1 << " to " << end + 1 << '\n';
    
    if(trace[end] == 0){
        cout << "Unavailable.! to go to from " << end + 1 
             << " to -> " << start + 1 << '\n';
    }
    else{
        while(end != start)
        {
            cout << end + 1 << "<-";
            end = trace[end];
        }
        cout << start + 1 << endl;
    }
    
}


int main()
{
    //Initialization
    vector<int> trace(maxx, 0);
    queue<int> Q;
    bool grid[maxx][maxx] = {false};
    
    int nodes, vertices;
    cout << "Please input the number of Node : \n";
    cin >> nodes;
    cout << "Please input the number of Vertices : \n";
    cin >> vertices;

    //Set value for all vertices.
    Read_input_from_user(grid, vertices); 

    //Read the necessary path
    int starting_position, finishing_position;
    cout << "Please Input the Starting Node : \n";
    cin >> starting_position;
    cout << "Please Input the Finishing Node : \n";
    cin >> finishing_position;
    //Decrease to fit with index of C++ start from 0->size-1
    starting_position--;
    finishing_position--;
    //Algorithm starts 
    Breadth_first_search(Q, trace, grid, starting_position, nodes);
    Trace_result(trace, starting_position, finishing_position, nodes);
    system("pause");
    return 0;
}

Suggestions me please, in procedure: void Breadth_first_search(queue<int> &Q, vector<int> &trace, bool grid[][maxx], int start, int nodes). I don't know Q.push, Q.pop, Q.front in C#, >"<.

[David Anton]

This should get you started - note that a couple of things, such as 'cin' are not converted:

using System;
using System.Collections.Generic;

private const int maxx = 20;

private void Read_input_from_user(bool[,] grid, int vertices)
{
	int u;
	int v;
	for (int x = 0; x < vertices; ++x)
	{
		Console.Write("Enter u : \t");
		cin >> u;
		u--;
		Console.Write("Enter v : \t");
		cin >> v;
		v--;
		grid[u, v] = true;
				grid[v, u] = true;
		Console.Write("---------------------\n");
	}
}

private void Breadth_first_search(Queue<int> Q, List<int> trace, bool[,] grid, int start, int nodes)
{
	int u;
	List<int> visited = new List<int>(maxx);
	Q.Enqueue(start);
	trace[start] = -1;
	visited[start] = 1;
	do
	{
		u = Q.Peek();
		Q.Dequeue();
		for (int v = 0; v < nodes; ++v)
		{
			if ((grid[u, v] == true) && visited[v] == 0)
			{
				Q.Enqueue(v);
				trace[v] = u;
				visited[v] = 1;
			}
		}
	}while (Q.Count > 0);
}

private void Trace_result(List<int> trace, int start, int end, int nodes)
{
	Console.Write("From _nodes");
	Console.Write(start + 1);
	Console.Write(" you can visit :\n");
	for (int v = 0; v < nodes; ++v)
	{
		if (trace[v] != 0)
		{
			Console.Write(" _nodes : ");
			Console.Write(v + 1);
			Console.Write(" , ");
		}
	}

	Console.Write("\n--------------------------------------------\n");
	Console.Write("The path from ");
	Console.Write(start + 1);
	Console.Write(" to ");
	Console.Write(end + 1);
	Console.Write('\n');

	if (trace[end] == 0)
	{
		Console.Write("Unavailable.! to go to from ");
		Console.Write(end + 1);
		Console.Write(" to -> ");
		Console.Write(start + 1);
		Console.Write('\n');
	}
	else
	{
		while (end != start)
		{
			Console.Write(end + 1);
			Console.Write("<-");
			end = trace[end];
		}
		Console.Write(start + 1);
		Console.Write("\n");
	}

}


static int Main()
{
	//Initialization
	List<int> trace = new List<int>(maxx);
	Queue<int> Q = new Queue<int>();
	bool[,] grid = {false};

	int nodes;
	int vertices;
	Console.Write("Please input the number of Node : \n");
	cin >> nodes;
	Console.Write("Please input the number of Vertices : \n");
	cin >> vertices;

	//Set value for all vertices.
	Read_input_from_user(grid, vertices);

	//Read the necessary path
	int starting_position;
	int finishing_position;
	Console.Write("Please Input the Starting Node : \n");
	cin >> starting_position;
	Console.Write("Please Input the Finishing Node : \n");
	cin >> finishing_position;
	//Decrease to fit with index of C++ start from 0->size-1
	starting_position--;
	finishing_position--;
	//Algorithm starts 
	Breadth_first_search(Q, trace, grid, starting_position, nodes);
	Trace_result(trace, starting_position, finishing_position, nodes);
	system("pause");
	return 0;
}

[Longbottomup]

Thank for help, but something wrong in code, ex: bool[,] grid = {false};
Can not, can you check?

[David Anton]

Try:

bool[,] grid = new bool[maxx, maxx];

[Longbottomup]

And this code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        private const int maxx = 20;

         void Read_input_from_user(bool[,] grid, int vertices)
        {
            int u;
            int v;
            for (int x = 0; x < vertices; ++x)
            {
                Console.Write("Enter u : \t");
                u = Convert.ToInt32(Console.ReadLine());
                u--;
                Console.Write("Enter v : \t");
                v = Convert.ToInt32(Console.ReadLine());
                v--;
                grid[u, v] = true;
                grid[v, u] = true;
                Console.Write("---------------------\n");
            }
        }

         void Breadth_first_search(Queue<int> Q, List<int> trace, bool[,] grid, int start, int nodes)
        {
            int u;
            List<int> visited = new List<int>(maxx);
            Q.Enqueue(start);
            trace[start] = -1;
            visited[start] = 1;
            do
            {
                u = Q.Peek();
                Q.Dequeue();
                for (int v = 0; v < nodes; ++v)
                {
                    if ((grid[u, v] == true) && visited[v] == 0)
                    {
                        Q.Enqueue(v);
                        trace[v] = u;
                        visited[v] = 1;
                    }
                }
            } while (Q.Count > 0);
        }

         void Trace_result(List<int> trace, int start, int end, int nodes)
        {
            Console.Write("From _nodes");
            Console.Write(start + 1);
            Console.Write(" you can visit :\n");
            for (int v = 0; v < nodes; ++v)
            {
                if (trace[v] != 0)
                {
                    Console.Write(" _nodes : ");
                    Console.Write(v + 1);
                    Console.Write(" , ");
                }
            }

            Console.Write("\n--------------------------------------------\n");
            Console.Write("The path from ");
            Console.Write(start + 1);
            Console.Write(" to ");
            Console.Write(end + 1);
            Console.Write('\n');

            if (trace[end] == 0)
            {
                Console.Write("Unavailable.! to go to from ");
                Console.Write(end + 1);
                Console.Write(" to -> ");
                Console.Write(start + 1);
                Console.Write('\n');
            }
            else
            {
                while (end != start)
                {
                    Console.Write(end + 1);
                    Console.Write("<-");
                    end = trace[end];
                }
                Console.Write(start + 1);
                Console.Write("\n");
            }

        }
         static int Main()
        {
            //Initialization
            List<int> trace = new List<int>(maxx);
            Queue<int> Q = new Queue<int>();
            bool[,] grid = new bool[maxx, maxx];
            int nodes;
            int vertices;
            Console.Write("Please input the number of Node : \n");
            //cin >> nodes;
            nodes = Convert.ToInt32(Console.ReadLine());
            Console.Write("Please input the number of Vertices : \n");
            //cin >> vertices;
            vertices = Convert.ToInt32(Console.ReadLine());
            //Set value for all vertices.
            Read_input_from_user(grid, vertices);
            
            //Read the necessary path
            int starting_position;
            int finishing_position;
            Console.Write("Please Input the Starting Node : \n");
            //cin >> starting_position;
            starting_position = Convert.ToInt32(Console.ReadLine());
            Console.Write("Please Input the Finishing Node : \n");
            //cin >> finishing_position;
            finishing_position = Convert.ToInt32(Console.ReadLine());
            //Decrease to fit with index of C++ start from 0->size-1
            starting_position--;
            finishing_position--;
            //Algorithm starts 
            Breadth_first_search(Q, trace, grid, starting_position, nodes);
            Trace_result(trace, starting_position, finishing_position, nodes);
            return 0;
        }
    }
}

But error in 3 procedure:
Read_input_from_user(grid, vertices);
Breadth_first_search(Q, trace, grid, starting_position, nodes);
Trace_result(trace, starting_position, finishing_position, nodes);

Error 3 An object reference is required for the non-static field, method, or property 'ConsoleApplication1.Program.Trace_result(System.Collections.Generic.List<int>, int, int, int)' C:\Users\Longbottom-up\Desktop\thu\ConsoleApplication1\ConsoleApplication1\Program.cs 127 13 ConsoleApplication1

Error 1 An object reference is required for the non-static field, method, or property 'ConsoleApplication1.Program.Read_input_from_user(bool[*,*], int)' C:\Users\Longbottom-up\Desktop\thu\ConsoleApplication1\ConsoleApplication1\Program.cs 111 13 ConsoleApplication1

Error 2 An object reference is required for the non-static field, method, or property 'ConsoleApplication1.Program.Breadth_first_search(System.Collections.Generic.Queue<int>, System.Collections.Generic.List<int>, bool[*,*], int, int)' C:\Users\Longbottom-up\Desktop\thu\ConsoleApplication1\ConsoleApplication1\Program.cs 126 13 ConsoleApplication1

I delete static, is that: int Main() , so not error in 3 procedure, i f5 and:

Error 1 Program 'C:\Users\Longbottom-up\Desktop\thu\ConsoleApplication1\ConsoleApplication1\obj\x86\Debug\ConsoleApplication1.exe' does not contain a static 'Main' method suitable for an entry point ConsoleApplication1
What's this?

[David Anton]

Make all the methods static. (Note: when our converter see C++ non-static methods outside of a class context, then it assumes that they are instance methods taken out of context, so that's why it didn't add 'static' for the methods).

[Longbottomup]

Make all the methods static. (Note: when our converter see C++ non-static methods outside of a class context, then it assumes that they are instance methods taken out of context, so that's why it didn't add 'static' for the methods).

Yes, very thanks. Code finish, but not work, >"<

[Longbottomup]

Look at C++: in Breadth_first_search(queue<int> &Q, vector<int> &trace, bool grid[][maxx], int start, int nodes) and Trace_result(vector<int> &trace, int start, int end, int nodes)
I see: &Q and &trace is passing value???? So i code in C#:ref queue<int> Q and ref List<int> trace.
So, after, whatever i edit, it seem error in: trace[start] = 1:

System.ArgumentOutOfRangeException was unhandled
Message=Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
Source=mscorlib
ParamName=index
StackTrace:
at System.ThrowHelper.ThrowArgumentOutOfRangeException()
at System.Collections.Generic.List`1.set_Item(Int32 index, T value)
at ConsoleApplication1.Program.Breadth_first_search(Queue`1& Q, List`1& trace, Boolean[,] grid, Int32 start, Int32 nodes) in C:\Users\Longbottom-up\Desktop\thu\ConsoleApplication1\ConsoleApplication1\Program.cs:line 35
at ConsoleApplication1.Program.Main() in C:\Users\Longbottom-up\Desktop\thu\ConsoleApplication1\ConsoleApplication1\Program.cs:line 126
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
InnerException:

[Longbottomup]

Can you test it on your VS, please.

[David Anton]

Look at C++: in Breadth_first_search(queue<int> &Q, vector<int> &trace, bool grid[][maxx], int start, int nodes) and Trace_result(vector<int> &trace, int start, int end, int nodes)
I see: &Q and &trace is passing value???? So i code in C#:ref queue<int> Q and ref List<int> trace.
So, after, whatever i edit, it seem error in: trace[start] = 1

No - you don't need the 'ref' unless you are changing the root object and want that passed back - changing an element of a list does not require 'ref'.

[Longbottomup]

No - you don't need the 'ref' unless you are changing the root object and want that passed back - changing an element of a list does not require 'ref'.

It's still error, not work when i input the node begin and node finish, not work, >"<.

[Longbottomup]

Same error.

[Longbottomup]

Thank for all, David, i think, i should be: Start level Zero. Thank for help.