Creating Matrix/map for Topological sort?

[siddmittal]

I am trying to simulate the logical circuits having NAND gates. I am reading the structure from .bench file. The structure of a circuit looks like below:

INPUT(1)
INPUT(2)
INPUT(3)
INPUT(6)
INPUT(7)


10 = NAND(1, 3)
11 = NAND(3, 6)
16 = NAND(2, 11)
19 = NAND(11, 7)
22 = NAND(10, 16)
23 = NAND(16, 19)

It can be seen that the inputs for Gate 22 are 10 and 16 which are also NAND gates. On the other hand, for gate 10, the inputs are 1 and 3 which are simple inputs. So, i need to sort the gates topologically. Although topological sort will not affect the output for this particular example but i have big circuits also in which topological sort is required. But we can use this simple example to do the topological sort.

My effort:

I thought to create a map which will keep the information about the gate name and its indegree. But i am unable to proceed further.

void Circuit::topologicalSort()			//topological sorting (for the mixed circuits)
{

	int counter = 0;
	std::map<string, int> unsortTopoList; //this list keeps a track of gate name and its Indegree
	
	for(int i=0; i<gates.size(); i++)
	{	
		string gate_name = gates[i]->getName();
		int INDEGREE = 0;
		for(int j=0; j<gates[i]->getNumInputs(); j++)
		{
			string gate_input_name = gates[i]->getInput(j)->getName();
			int result = ( findGate(gate_input_name) ); // We trying to check if the given gate's input is also a gate or not.
			INDEGREE = INDEGREE + result;
			result = 0;
		}
		
		unsortTopoList[ gates[i]->getName() ] = INDEGREE; //This list will tell that the indegree of gate name "gate_input_vec[i][0]"
		counter++;
	}

	for(int i=0; i<counter; i++)
	{
		cout<<"\nGate: "<<gates[i]->getName()<<"  is having Indegree: "<<unsortTopoList[ gates[i]->getName() ];
	}

	cout<<"\n";
}

int Circuit::findGate( string gateName )
{
	int result = 0;

	for(int i=0; i<gates.size(); i++)
	{
		if( gateName.compare( gates[i]->getName() )  ==0 ) //"==0" means that they are same.
		{
			result= 1;
			break;
		}
		else
			result= 0;
	}
	
	return result;
}