How to take the input

#1

I am having difficulty in how to use true and false given in this problem used for making tree

#2 
node *build(string s){
    if(s=="true"){
        int d;
        cin>>d;
        node *root = new node(d);
        string l;
        cin>>l;
        if(l=="true"){
        root->left=build(l);
        }
        string r;
        cin>>r;
        if(r=="true"){
        root->right=build(r);
        }
        return root;
	}
	return NULL;
}