Updating std::map with value as struct data type

In the below code I am using std::map&myMap as reference

I am using the map value dataNode to update the values of start_time and end_time but I see that these values are not updated and I get the

following prints in widthOfBinaryTree when I print

0 2147483647 -2147483648

1 2147483647 -2147483648

2 2147483647 -2147483648

Why would not the values of start_time and end_time not get updated at every level of the tree .

class Solution {

public:

    typedef struct dataNode
    {
        int start_time =INT_MAX;
        int end_time = INT_MIN;
    };


    int widthOfBinaryTreeRecursion(TreeNode* root, int level, int sideLevel, bool left, std::map<int ,dataNode>&myMap)
    {

        if(root == nullptr)
        {
            return 0 ;
        }

        auto element = myMap[level];

        widthOfBinaryTreeRecursion(root->left , level+1 , sideLevel*2 , true ,myMap);

        if(left && sideLevel < element.start_time)
        {
            cout << "start" << " " <<element.start_time << " " << sideLevel  << " " <<root->val <<" " << level <<endl;

            element.start_time = sideLevel;
        }

        if(!left && sideLevel > element.end_time)
        {
             cout <<"end" <<" " <<  element.end_time << " " << sideLevel  << " " <<root->val <<" " << level <<endl;

              element.end_time = sideLevel;
        }

        widthOfBinaryTreeRecursion(root->right, level+1 ,sideLevel*2+1, false, myMap);

        return 0;
    }

    int widthOfBinaryTree(TreeNode* root) 
    {
        std::map<int , dataNode>myMap;

        widthOfBinaryTreeRecursion(root, 0, 1, true,myMap);

        for(auto itr : myMap)
        {
            cout << itr.first <<" " << itr.second.start_time << endl;
        }

        return 0;
    }
};