Directed graph
 

Hi everyone, I am a U.student from China, I would like ask a question about my assignment.

For the directed graph, I would like to perform topological sort for sorting up nodes, but I encountered some problem in queue which is able to be removed or added with certain elements.

My question is how I can perform queue in topological sort function? my algorithm is here

// The topological sort

void DGraph::topologicalSort(){

        if(isTPSorted==false){

                int j=0;

                Queue ts;

                while(ts.size()!=0)

                        /*dequeue()  dequeue for queue*/

                for(int i=0;i<50;i++){

                        if (visitedTable[i]>=0 && inDegTable[i] == 0)

                                /*enqueue(i)  enqueue for queue*/

                }

                while(ts.size()>0){                           

                        predTable[j]=dequeue();/*putting into predTable*/

                        int a=predTable[j];

                        j++;

                        for(int k=0;k<50;k++){

                                if(adjMatrix[a][k]==1){ 

                                        inDegTable[k]--;

                                        if (inDegTable[k] == 0){

                                             /*enqueue(k) enqueue for queue*/

                                        }

                                }

                                

                        }

                }

                isTPSorted = true;

        }

        return;

}

my professor gave a hint to perform queue:

In the implementation of the topological sort, a queue data structure is required. he said I can use the queue from the standard template library. Here are some short descriptions of the functions provided by the STL queue.

empty : true if the queue has no elements
front pop: returns a reference to the first
push : element of a queue removes the first element of a queue adds an element to the end of the queue

For example, include header <queue> and declare my queue as std::queue <int> Queue. And use push as Queue.push(int).

I could find some information in http://www.sgi.com/tech/stl/queue.html. but I don't catch up the point.

Thank you very much