Sorting a list by last name

Question

Jason Chimera SE 7039990101

Mike Knuble SSE 7039990102

Karl Alzner JSE 7039990202

Tom Poti SE 7039990203

Alex Ovechkin EGM 7039990001

I am trying to read in the information above from a file and sort it by last name. How can I fix this error:

Error:expected a ':'

for the strings I declared in the EmployeeInformation class?

 class EmployeeInformation {
  public string firstName;
  public string lastName;
  public string title;
  public string phonenumber;

EmployeeInformation(&firstName, &lastName, &title, &phonenumber)
{
    this->firstName = firstName;
    this->lastName = lastName;
    this->initials = title;
    this->id = phoneumber;
}
};


 #include <vector>
 #include <algorithm>
 #include <iostream>
 #include <fstream>

 using namespace std;

int main(int argc, char**argv) {

ifstream file;
file.open("employees.txt");

if (!file.is_open())
    cout << "Error opening file";

vector<EmployeeInformation> employees;
while (!file.eof())
{

    string firstName, lastName, title, phonenumber;
    file >> firstName >> lastName >> title >> phonenumber;
    EmployeeInformation person(firstName, lastName, title, phonenumber);
    employees.push_back(person);
    // end file
}
sort(employees.begin(), employees.end(), [](EmployeeInformation a, EmployeeInformation b) { return a.lastName < b.lastName });

for (EmployeeInformation i : employees)
    // print person info in sorted order

return 0;

}

Oh where to start. Maybe you should double check how to [create a class](http://www.cplusplus.com/doc/tutorial/classes/) — NathanOliver, May 13 '15 at 20:15
and double check [how NOT to read a file](https://stackoverflow.com/questions/5605125/why-is-iostreameof-inside-a-loop-condition-considered-wrong). — The Paramagnetic Croissant, May 13 '15 at 20:17
You use UNIIX tools. `sort -k2 `. You don't need to write code for this. — Martin York, May 13 '15 at 20:22
Maybe you could write a *comparison function* for use with `std::sort`? I'd give you an example, but I don't know how to search the internet for "c++ example sort function". — Thomas Matthews, May 13 '15 at 20:30

score 7 · Answer 1 · edited Apr 13 '17 at 12:40

Lot of minor errors.

Public section.

In C++ public is followed by ':' to mark a section. Also you need to include the string definition. Which lives in the std:: namespace.

  public: std::string firstName;
  public: std::string lastName;
  public: std::string title;
  public: std::string phonenumber;

C++ is a very pedantic on types.

You need to specify the types of all parameters:

EmployeeInformation(string const& firstName, string const & lastName, string const& title, string const& phonenumber)

unknown names:

this->initials = title;
  //  ^^^^^^^^   Not a member of this class. Did you mean title.
this->id = phoneumber;
  //  ^^         Not a member of this class. Did you mean phoneumber

Statements are terminated by ';'

return a.lastName < b.lastName
                       //      ^^^^^   missing here.

Once you have those fixed it compiles. But I would take the fixed version to code review for a more detailed break down.

When all complete main looks like this:

int main(int argc, char**argv)
{
    std::ifstream file("employees.txt");

    // Read data into vector
    std::vector<EmployeeInformation> employees(std::istream_iterator<EmployeeInformation>(file),
                                               (std::istream_iterator<EmployeeInformation>()));

    // Sort container.
    std::sort(std::begin(employees), std::end(employees),
              [](EmployeeInformation const& lhs, EmployeeInformation const& rhs) { return lhs.lastName < rhs.lastName;});

    // Copy container to stream.
    std::copy(std::begin(employees), std::end(employees),
              std::ostream_iterator<EmployeeInformation>(std::cout));
}

Remy Lebeau · Answer 2 · 2015-05-13T21:59:03.083

Your class is not declared correctly. For instance, you cannot omit data types from the constructor's parameters.

You are also not reading the file correctly.

Try something more like this:

#include <vector>
#include <algorithm>
#include <iostream>
#include <fstream>
#include <string>
#include <sstream>

using namespace std;

class EmployeeInformation
{
public:
    string firstName;
    string lastName;
    string title;
    string phoneNumber;

    EmployeeInformation(const string &_firstName, const string &_lastName, const string &_title, const string &_phonenumber) :
        firstName(_firstName),
        lastName(_lastName),
        title(_title),
        phoneNumber(_phoneNumber)
    {
    }
};

int main(int argc, char**argv)
{
    ifstream file;

    file.open("employees.txt");
    if (!file.is_open())
    {
        cout << "Error opening file";
        return 0;
    }

    vector<EmployeeInformation> employees;
    string line;

    while (getline(file, line))
    {
        string firstName, lastName, title, phonenumber;
        istringstream iss(line);
        iss >> firstName >> lastName >> title >> phonenumber;
        EmployeeInformation person(firstName, lastName, title, phonenumber);
        employees.push_back(person);
    }

    sort(employees.begin(), employees.end(), [](const EmployeeInformation &a, const EmployeeInformation &b) { return a.lastName < b.lastName; });

    for (EmployeeInformation i : employees)
    {
        // print person info in sorted order
        cout << i.lastName << " " << i.firstName << " " << i.title << " " i.phoneNumber << endl;
    }

    return 0;
}

The same way you print out anything else - pass the desired values to `std::cout` as needed. I updated my answer to show that. — Remy Lebeau, May 13 '15 at 21:59

score 3 · Answer 3 · answered May 13 '15 at 20:28

Your syntax for access modifiers is incorrect (you're using Java style rather than C++). In C++ you would declare this fully public class like this:

 class EmployeeInformation {
 public:
   string firstName;
   string lastName;
   string title;
   string phonenumber;
   //...
};

If you really do want to make all the data public, you could also use a struct instead of a class, since the members of structs are public by default.

score 2 · Answer 4 · answered May 13 '15 at 20:32

First of all your variable declaration in class is wrong.Then in the constructor,you are not telling the data types.See this

 class EmployeeInformation {
public:
string firstName;
string lastName;
string title;
string phonenumber;

EmployeeInformation(string &firstName,string &lastName,string &title,string &phonenumber)
{
this->firstName = firstName;
this->lastName = lastName;
this->title = title;            //there is no variable named initial in class
this->phonenumber = phonenumber; //there is no variable named id in class
}
};

Then you are missing a semicolon.

sort(employees.begin(), employees.end(), [](EmployeeInformation a, EmployeeInformation b) { return a.lastName < b.lastName; });  //there should be a semicolon after return statement