DAG.cpp

#include <iostream>
#include <string>
#include <unordered_map>
using namespace std;
class DAG
{
public:
    char label;
    char data;
    DAG *left;
    DAG *right;

    DAG(char x)
    {
        label = '_';
        data = x;
        left = NULL;
        right = NULL;
    }
    DAG(char lb, char x, DAG *lt, DAG *rt)
    {
        label = lb;
        data = x;
        left = lt;
        right = rt;
    }
};

int main()
{
    int n;
    n = 3;
    string st[n];
    st[0] = "A=x+y";
    st[1] = "B=A*z";
    st[2] = "C=B/x";
    unordered_map<char, DAG *> labelDAGNode;

    for (int i = 0; i < 3; i++)
    {
        string stTemp = st[i];
        for (int j = 0; j < 5; j++)
        {
            char tempLabel = stTemp[0];
            char tempLeft = stTemp[2];
            char tempData = stTemp[3];
            char tempRight = stTemp[4];
            DAG *leftPtr;
            DAG *rightPtr;
            if (labelDAGNode.count(tempLeft) == 0)
            {
                leftPtr = new DAG(tempLeft);
            }
            else
            {
                leftPtr = labelDAGNode[tempLeft];
            }
            if (labelDAGNode.count(tempRight) == 0)
            {
                rightPtr = new DAG(tempRight);
            }
            else
            {
                rightPtr = labelDAGNode[tempRight];
            }
            DAG *nn = new DAG(tempLabel, tempData, leftPtr, rightPtr);
            labelDAGNode.insert(make_pair(tempLabel, nn));
        }
    }
    cout << "Label      ptr      leftPtr       rightPtr" << endl;
    for (int i = 0; i < n; i++)
    {
        DAG *x = labelDAGNode[st[i][0]];
        cout << st[i][0] << "            " << x->data << "            ";
        if (x->left->label == '_')
            cout << x->left->data;
        else
            cout << x->left->label;
        cout << "          ";
        if (x->right->label == '_')
            cout << x->right->data;
        else
            cout << x->right->label;
        cout << endl;
    }
    return 0;
}