How to access class object from a function - c++

Question

Ok So I have abit of a problem with my code that I cant seem to find the solution for. Im writing a program that will work like a phonebook for your phone. And everything that happens will be saved in a .txt file. So when the program starts it will always read from the same file and put that into class objects called "person" and then you will be able to edit/delete/add new contacts and then it gets rewriten to the file.
The problem im having right now is that I want to make more of the code into functions instead of having it all in the main folder. So as you can see from the two last functions, one should read from the file and the other should write to the file. What I want to do is to replace all the code in main() that has to do with readToFile and writeToFile. Also i would like to be able to put the writeToFile function after every case switch action like edit/delete/add. So that you dont have to choose to write to the file. It just does that automatically.
Can I somehow use pointers/references for this or how do i get access to the "person" objects in my functions.
First time asking a question here so feel free to educate me if i did something wrong.
Here is the code:
#include <string>
#include <iostream>
#include <fstream>
using namespace std;
void printline(char, int);
bool name_valid(string);
class contact
{
public:
string fName, lName, adress, epost, mobileNo, birthday;
//initialize the contact by a default value
contact() : fName(""), lName(""), adress(""), epost(""), mobileNo(""), birthday("")
{}
// Write all contacts to the file.
bool writeToFile()
{
if (fName != "")
{
cout << "Name: " << fName << " " << lName << "\n" << "Mobilenumber: " << mobileNo << "\n" << "Adress: " << adress << "\n" << "Email: " << epost << "\n" << "Birthday: " << birthday << endl;
return 1; //Success!!
}
else
{
cout << " Fail!" << endl;
return 0; //Fail!!
}
}
//Show all contacts
bool showAll()
{
if (fName != "")
{
cout << "Name: " << fName << " " << lName << "\n" << "Mobilenumber: " << mobileNo << "\n" << "Adress: " << adress << "\n" << "Email: " << epost << "\n" << "Birthday: " << birthday << endl;
return 1; //Success!!
}
else
return 0; //Fail!!
}
// Search
bool Search(string search_word)
{
if (search_word == fName)
{
cout << "Name: " << fName << " " << lName << "\n" << "Mobilenumber: " << mobileNo << "\n" << "Adress: " << adress << "\n" << "Email: " << epost << "\n" << "Birthday: " << birthday << endl;
return 1;
}
else
return 0;
}
// Check if a name exists or not
bool name_exists(string tname)
{
if (tname == fName)
return 1;
else
return 0;
}
// The contact object is initialized by valid values
bool addContact(string new_fName, string new_lName, string new_adress, string new_epost, string new_mobileNo, string new_birthday )
{
if (fName == "")
{
fName = new_fName;
lName = new_lName;
adress = new_adress;
epost = new_epost;
mobileNo = new_mobileNo;
birthday = new_birthday;
return 1; // Success !!
}
else
return 0; // Failure !!
}
//edits the contact details
bool edit(string);
bool erase(string new_name)
{
if (new_name == fName)
{
fName = "";
lName = "";
adress = "";
epost = "";
mobileNo = "";
birthday = "";
return 1;
}
else
return 0;
}
};
// Edits the contact
bool contact::edit(string name_check)
{
string new_fName, new_lName, new_adress, new_epost, new_mobileNo, new_birthday;
if (name_check == fName)
{
cin.ignore();
cin.clear();
cout << "Enter new first name: ";
getline(cin,new_fName);
cout << "Enter new lastname: ";
getline(cin,new_lName);
cout << "Enter new adress: ";
getline(cin,new_adress);
cout << "Enter new epost: ";
getline(cin,new_epost);
cout << "Enter new birthday: ";
getline(cin,new_birthday);
fName = new_fName;
lName = new_lName;
adress = new_adress;
epost = new_epost;
birthday = new_birthday;
return 1;
}
else
return 0;
}
int main()
{
contact person[100];
ifstream infile("Phonebook.txt");
string temp_fName, temp_lName, temp_adress, temp_epost, temp_mobilNo, temp_birthday;
int counter, choice, i;
bool flag;
bool cancel_flag;
// Read from file to contact person
string ignoreName, ignoreCell, ignoreAdress, ignoreEmail, ignoreBirthday;
string fileFirstname, fileLastname, fileCell, fileAdress, fileEmail, fileBirthday;
// Goes through the text file and put all the names in the contact class
while (!infile.eof())
{
getline(infile, ignoreName, ' ');
getline(infile, fileFirstname, ' ');
getline(infile, fileLastname);
getline(infile, ignoreCell, ' ');
getline(infile, fileCell);
getline(infile, ignoreAdress, ' ');
getline(infile, fileAdress);
getline(infile, ignoreEmail, ' ');
getline(infile, fileEmail);
getline(infile, ignoreBirthday, ' ');
getline(infile, fileBirthday);
// Check if the file is empty
if (!infile)
{
break;
}
for (i = 0; i < 100; i++)
if (person[i].addContact(fileFirstname, fileLastname, fileAdress, fileEmail, fileCell, fileBirthday))
{
cout << "\nContact added successfully!" << endl;
flag = 1;
break;
}
}
infile.close();
ofstream outfile("Phonebook.txt");
cout << "=========== Your Phonebook ==========" << endl;
do
{
cout << "\n\n";
printline('-', 25);
cout << "1. Add Contact" << endl
<< "2. Edit Contact" << endl
<< "3. Delete Contact" << endl
<< "4. Search" << endl
<< "5. Show All Contacts" << endl
<< "6. Write All Contacts To File." << endl
<< "0. Exit" << endl << endl
<< "Your choice... ";
cin >> choice;
system("cls");
printline('-', 20);
cancel_flag = 0;
flag = 0;
counter = 0;
switch (choice)
{
case 0:
return 0;
break;
// Adds a new contact
case 1:
cout << "Add New Contact\t\t\t\tpress - to cancel" << endl;
printline('-', 25);
counter = 0;
// Loop until correct contact info is untered
do
{
flag = 0;
if (counter)
cout << "Try again \t\t\t\tpress - to cancel" << endl;
//count how many times the do-while loop executes
counter++;
cin.ignore();
cin.clear();
cout << "First Name: ";
getline(cin, temp_fName);
cout << "Last Name: ";
getline(cin, temp_lName);
cout << "Adress: ";
getline(cin, temp_adress);
cout << "Email: ";
getline(cin, temp_epost);
cout << "Mobile Number: ";
getline(cin, temp_mobilNo);
cout << "Birthday: ";
getline(cin, temp_birthday);
if (temp_fName == "-")
{
cancel_flag = 1;
break;
}
for (i = 0; i < 100; i++)
{
if (person[i].name_exists(temp_fName))
{
cout << "The name you entered is already there"
"in the phonebook, entere a different name." << endl;
flag = 1;
break;
}
}
} while (!name_valid(temp_fName) || flag);
if (cancel_flag)
{
system("cls");
break;
}
//This loop adds the contact to the phonebook
for (i = 0; i < 100; i++)
if(person[i].addContact(temp_fName, temp_lName, temp_adress, temp_epost, temp_mobilNo, temp_birthday))
{
cout << "\nContact added successfully!" << endl;
flag = 1;
break;
}
if (!flag)
cout << "Memory full! Delete some contacts first." << endl;
break;
// Edits an existing contact
case 2:
cout << "Enter a contact name to edit \t\t\t\tpress - to cancel" << endl;
cin >> temp_fName;
// Cancel operation
if (temp_fName == "-")
{
system("cls");
break;
}
for (i = 0; i < 100; i++)
if (person[i].edit(temp_fName))
{
cout << "Edited Successfully!" << endl;
flag = 1;
break;
}
if (!flag)
cout << "Contact name not found!" << endl;
break;
//Delete a contact
case 3:
do
{
if (counter)
cout << "Try again" << endl;
counter++;
cout << "Enter a contact name to delete: \t\t\t\tpress - to cancel" << endl;
cin >> temp_fName;
// Cancel operation
if (temp_fName == "-")
{
system("cls");
break;
}
//Final Confirmation
for (i = 0; i < 100; i++)
if (person[i].name_exists(temp_fName))
{
flag = 1;
cout << "Are you sure you want to delete (1/0)" << endl;
int yes;
cin >> yes;
if (!yes)
{
system("cls");
cancel_flag = 1;
}
break;
}
if (!flag)
cout << "Contact name not found!" << endl;
if (cancel_flag)
break;
// This code deletes the contact
if (flag)
{
for (i = 0; i < 100; i++)
if (person[i].erase(temp_fName))
{
cout << "Deleted successfully!" << endl;
break;
}
}
} while (!flag);
break;
// Search a contact
case 4:
do
{
if (counter)
cout << "Try again" << endl;
counter++;
cout << "Search a name: \t\t\t\tpress - to cancel" << endl;
cin >> temp_fName;
// Cancel operation
if (temp_fName == "-")
{
system("cls");
break;
}
for (i = 0; i < 100; i++)
if (person[i].Search(temp_fName))
{
flag = 1;
break;
}
if (!flag)
cout << "Contact namew not found!" << endl;
} while (!flag);
break;
// Show all the contacts
case 5:
cout << "Showing Contacts" << endl;
printline('-', 25);
for (i = 0; i < 100; i++)
{
if (person[i].showAll())
{
flag = 1;
cout << "\n\n";
}
}
if (!flag)
cout << "No contacts found!" << endl;
break;
case 6:
// Write to file
cout << "Writing to file." << endl;
printline('-', 25);
for (int i = 0; i < 100; i++)
{
if (person[i].fName != "")
{
outfile << "Name: " << person[i].fName << " " << person[i].lName << "\n" << "Mobilenumber: " << person[i].mobileNo << "\n" << "Adress: " << person[i].adress << "\n" << "Email: " << person[i].epost << "\n" << "Birthday: " << person[i].birthday << "\n\n\n\n";
flag = 1;
cout << "\n\n";
}
}
break;
}
}while (1);
return 0;
}
//prints a line
void printline(char ch, int size)
{
for (int i = 0; i < size; i++)
cout << ch;
cout << "\n";
}
//Contact name validation
bool name_valid(string tname)
{
if (tname.size() > 20)
{
cout << "Invalid name!\nEnter a name within 20 characters!" << endl;
return 0;
}
else if (tname == "")
{
cout << "Invalid Name!\nName cannot be blank" << endl;
return 0;
}
else
return 1;
}
void writeToFile()
{
cout << "Writing to file." << endl;
printline('-', 25);
for (int i = 0; i < 100; i++)
{
if (person[i].fName != "")
{
outfile << "Name: " << person[i].fName << " " << person[i].lName << "\n" << "Mobilenumber: " << person[i].mobileNo << "\n" << "Adress: " << person[i].adress << "\n" << "Email: " << person[i].epost << "\n" << "Birthday: " << person[i].birthday << "\n\n\n\n";
flag = 1;
cout << "\n\n";
}
}
}
void readfromfile()
{
ifstream infile("Phonebook.txt");
string ignoreName, ignoreCell, ignoreAdress, ignoreEmail, ignoreBirthday;
string fileFirstname, fileLastname, fileCell, fileAdress, fileEmail, fileBirthday;
// Goes through the text file and put all the names in the contact class
while (!infile.eof())
{
getline(infile, ignoreName, ' ');
getline(infile, fileFirstname, ' ');
getline(infile, fileLastname);
getline(infile, ignoreCell, ' ');
getline(infile, fileCell);
getline(infile, ignoreAdress, ' ');
getline(infile, fileAdress);
getline(infile, ignoreEmail, ' ');
getline(infile, fileEmail);
getline(infile, ignoreBirthday, ' ');
getline(infile, fileBirthday);
// Check if the file is empty
if (!infile)
{
break;
}
for (int i = 0; i < 100; i++)
if (person[i].addContact(fileFirstname, fileLastname, fileAdress, fileEmail, fileCell, fileBirthday))
{
cout << "\nContact added successfully!" << endl;
flag = 1;
break;
}
}
infile.close();
}

Answer 1

Just pass in an array to the function (and others which are needed). Now the size of the array is known beforehand so we can protect it from array decay too. It'll look something like this,
void writeToFile(contact(&person)[100], std::fstream& outfile, bool& flag) { ... }
void readfromfile(contact(&person)[100], bool& flag) { ... }
Note that were passing in the others (flag and outfile) using the reference so that the actual variable can be altered.
From the two, I would recommend using the second option. Its clean, simple and safe (if you may).
Note: Try not to use using namespace std;. It not a good practice and basically your taking the std namespace and putting it in the global namespace. Now that namespace is huuuuggeeeeee. Later to access its objects and stuff, use :: operator.