char* obj_name = new char [64];
cin >> obj_name;
Classname obj_name;

class Text : public TBaseClass {};
class Word : public TBaseClass {};
TBaseClass n;
if (obj_name == "Text") {
    n = new Text();
} else if (obj_name == "Word") {
    n = new Word();
} else {
    n = NULL;
    cout << "unknown object name";
}

#include <iostream>
#include <string>
#include <map>

using namespace std;

class CustomClass{
public:
    //...
    void test(){
        cout << "test" << endl;
    }
};

int main(){
    map<string, CustomClass*> classes;

    string className;
    cin >> className;

    CustomClass *one = new CustomClass();
    classes.insert(make_pair<string, CustomClass>(className, one));

    classes[className]->test();
    // или classes["ручками пишем"]->test();

    return 0;
}