I have same type of errors in my program please help me out....
I am just a Beginner in C++....

#include "iostream"
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
using namespace std;

class form
{
private:
    char fname[20];
    char lname[20];
    char add[50];
    char city[25];
    int contact;
public:
        form()
    {
    fname[20]='\0';
    lname[20]='\0';
    add[50]='\0';
    city[25]='\0';
    contact=0;
    }
    void input()
    {
        system("cls");
        cout << "----------------------------------------------" << endl;
        cout << "**********************************************" << endl;
        cout << "----------------------------------------------" << endl;
        cout << "\nEnter First Name: " << endl;
        cin.getline(fname, 20);
        cout << "\nEnter Last Name Name: " << endl;
        cin.getline(lname, 20);
        cout << "\nEnter Your Address: " << endl;
        cin.getline(add, 50);
        cout << "\nEnter Your City: " << endl;
        cin.getline(city, 25);
        cout << "Enter Your Contact: ";
        cin >> contact;
        cout << endl;
        cout << "----------------------------------------------" << endl;
        cout << "**********************************************" << endl;
        cout << "----------------------------------------------" << endl;

    }//end of input-function
    void display()
    {
        system("cls");
        cout << "----------------------------------------------" << endl;
        cout << "**********************************************" << endl;
        cout << "----------------------------------------------" << endl;
        cout << "Full Name: " << fname<< " " << lname << endl;
        cout << "Address: " << add << endl;
        cout << "Contact: " << contact << endl;
        cout << "----------------------------------------------" << endl;
        cout << "**********************************************" << endl;
        cout << "----------------------------------------------" << endl;
    }//end of display-function


};//End of class-form

class complaint_type
{

public:
    void low_speed()
    {
        system("cls");
        cout << "Your Device Parameters are LOW" << endl;
        cout << "Your Complain Number is 91" << endl;
        cout << "Call 1218 for information" << endl;
        cout << "Thank You for Using PTCL" << endl;
    }
    void disconnecting()
    {
        system("cls");
        cout << "Problem in device";
        cout << "Please goto EVO ONE STOP SHOP for repair" << endl;
        cout << "Your Complain Number is 19" << endl;
        cout << "Call 1218 for information" << endl;
        cout << "Thank You for Using PTCL" << endl;


    }
    void bill()
    {
        system("cls");
        cout << "Your Complain Number is 81" << endl;
        cout << "Call 1218 for for information" << endl;
        cout << "Thank You for Using PTCL" << endl;
    }
    void browsing()
    {
        system("cls");
        cout << "Your Complain Number is 45" << endl;
        cout << "Call 1218 for information" << endl;
        cout << "Thank You for Using PTCL" << endl;
    }
    void voice()
    {
        system("cls");
        cout << "Your Complain Number is 65" << endl;
        cout << "Call 1218 for information" << endl;
        cout << "Thank You for Using PTCL" << endl;
    }
    void signal()
    {
        system("cls");
        cout << "Your Complain Number is 33" << endl;
        cout << "Call 1218 for information" << endl;
        cout << "Thank You for Using PTCL" << endl;

    }



};//end of coplaint-type

class PTCL
{

private:
    complaint_type *obj;
    int select,lnum,MDN;
public:

    void EVO()
    {
        system("cls");
        cout << "------------Welcome to EVO Complaint------------" << endl;
        cout << "Enter Your MDN: ";
        cin >> MDN;
        cout << endl;
        cout << "1. Low Speed" << endl;
        cout << "2. Signal" << endl;
        cout << "3. Browsing" << endl;
        cout << "4. Disconnecting" << endl;
        cout << "5. Billing" << endl;
        cout << "Enter Your Section: " << endl;
        cin >> select;
        if (select == 1)
        {
            obj->low_speed;
        }
        else if (select==2)
        {
            obj->signal;
        }
        else if (select == 3)
        {
            obj->browsing;
        }
        else if (select == 4)
        {
            obj->disconnecting;
        }
        else if (select == 5)
        {
            obj->bill;
        }
        else
        {
            cout << "\nWrong Selection";
        }

    }
    void Broadband()
    {
        system("cls");
        cout << "------------Welcome to Broadband Complaint------------" << endl;
        cout << "Enter Your Number With area code: ";
        cin >> lnum;
        cout << endl;
        cout << "1. Low Speed" << endl;
        cout << "2. Browsing" << endl;
        cout << "3. Disconnecting" << endl;
        cout << "4. Billing" << endl;
        cout << "Enter Your Section: " << endl;
        cin >> select;
        if (select == 1)
        {
            obj->low_speed;
        }

        else if (select == 2)
        {
            obj->browsing;
        }
        else if (select == 3)
        {
            obj->disconnecting;
        }
        else if (select == 4)
        {
            obj->bill;
        }
        else
        {
            cout << "\nWrong Selection";
        }

    }
    void Landline()
    {
        system("cls");
        cout << "------------Welcome to LandLine Complaint------------" << endl;
        cout << "Enter Your Number With area code: ";
        cin >> lnum;
        cout << endl;
        cout << "1. Voice" << endl;
        cout << "2. Disconnecting" << endl;
        cout << "3. Billing" << endl;
        cout << "Enter Your Section: " << endl;
        cin >> select;
        if (select == 1)
        {
            obj->voice;
        }

        else if (select == 2)
        {
            obj->disconnecting;
        }
        else if (select == 3)
        {
            obj->bill;
        }

        else
        {
            cout << "\nWrong Selection";
        }

    }


};
int main(int argc, char *argv[])
{
    PTCL *obj2;
    cout << "-----------------Welcome to--------------------" << endl;
    cout << "----------PTCL Complain Management-------------" << endl;
    cout << "\n\n";
    cout << "1. LandLine" << endl;
    cout << "2. Broadband" << endl;
    cout << "3. EVO Wireless" << endl;
    cout << "4. Form" << endl;
    int a;
    cout << "Enter Selection: ";
    cin >> a;
    switch (a)
    {
    case 1:
    {

              obj2->Landline;
              break;
    }
    case 2:
    {
              obj2->Broadband;
              break;
    }
    case 3:
    {
              obj2->EVO;
              break;
    }
    default:
    {
               cout << "Wrong Input";
               break;
    }
    }

    return 0;
}

Just the function or member function name won't do, the argument list is required even if it's empty. For example:

obj2->Landline(); // Notice the parentheses

Also note that you'll immediately get a runtime failure because obj2 doesn't point to anything. Either make it a regular object:

PCTL obj2;

...

obj2.Landline();

Or have the pointer point to an object:

PCTL base_obj;
PCTL *obj2 = &base_object;

obj2->Landline();
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