Question

I am learning c++, and I just got to the object oriented chapter. I have a question about creating objects inside if statements.

The problem I’m working on says to create a class that will display a report header. The class has a default constructor that sets the company name and report name to a generic thing, and also, if the user wants, has a constructor that takes two arguments (strings company name and report name).

The problem says, specifically, “A two-parameter default constructor should allow these [company and report names] to be specified at the time a new Report object is created. If the user creates a Report object without passing any arguments, use the default values. Otherwise, use user specified values for the names.”

So my question is, how to create these objects? I understand how to create an object without any arguments (i.e. Report newobj;), and also with arguments (i.e. Report newobj(string string);). Basically, I get how to create these objects initially at the top of my main function. But is it possible to create them inside if statements based on user choices? Here is what I have so far and, obviously, it doesn’t work:

#include <iostream>
#include <string>
#include "report.h"
using namespace std;

bool enter_company_name();           // return true if user wants to enter company name
bool print_form();              // return true if user wants to print in formatted output

int main()
{
  string company_name,
    report_name;
  bool name = false,
    format = false;

  name = enter_company_name();
  format = print_form();

  if (name)
    {
      cout << "Enter company name: ";
      getline(cin, company_name);
      cout << "Enter report name: ";
      getline(cin, report_name);
      Report header(company_name, report_name);  // THIS IS MY PROBLEM
    }
  else
      Report header;  // THIS IS MY PROBLEM

  if (format)
    header.print_formatted();
  else
    header.print_one_line();

  return 0;
}

bool enter_company_name()
{
  char choice;

  cout << "Do you want to enter a name?\n>";
  cin >> choice;

  if (choice == 'y' || choice == 'Y')
    return true;
  else
    return false;
}

bool print_form()
{
  char choice;

  cout << "Do you want to print a formatted header?\n>";
  cin >> choice;

  if (choice == 'y' || choice == 'Y')
    return true;
  else
    return false;
}

So I want to create an object using default values if none are specified, or create one with the user values if that’s the choice given. I just can’t figure out how to do it interactively in c++. I have not been able to find any similar questions anywhere so far.

The closest thing I’ve come across uses pointers to do something similar to what I want to do, but the book I’m using has not gotten to pointers yet, and I want to try to figure out a way to do it that stays within the bounds of the chapter I’m working in (i.e. not using pointers).

I didn’t include the header file or class implementation file because I don’t think they are relevant here.

Thank you in advance!

Answer 1

I don’t know if I understood your question correctly but can’t you just declare report before the if/else block and then initialize inside it?

Report header;

if (...) {
  header = Report();
else
  header = Report(name,company);

Or in a shorter way:

Report header; // calls default constructor

if (shouldInitializeWithParams) {
  header = Report(name,company);
}

Of course this requires you to have the empty constructor defined.