Member Avatar for V1RuZ

Hi out there.

I can't get the constructors in my header files to work.

Here's a copy of my header file code:

#ifndef GUARD_PHEADER_H
#define GUARD_PHEADER_H

//The header file for the Person.cpp.
//person_header.h

#include <iostream>
#include <string>

//Person class declaration
class Person {
public:
       std::istream& read_surname(std::istream&);
       std::istream& read_name(std::istream&);
       std::istream& read_phone(std::istream&);
       std::istream& read_age(std::istream&);
       std::istream& read_weight(std::istream&);
       std::string& read_phone(std::string&);
       int& read_age(int&);
       double& read_weight(double&);
       std::string get_name() const { return name; }
       std::string get_surname() const { return surname; }
       std::string get_phone() const { return phone; }
       int get_age() const { return age; }
       double get_weight() const { return weight; }
       person(std::string&, std::string&, std::string&, int&, double&);
       Person(std::ifstream&);
private:
        std::string surname;
        std::string name;
        std::string phone;
        int age;
        double weight;
    };    
#endif

And a copy of the function code:

//Constructor for Person

Person::person(std::ifstream& in) : surname(0), name(0), phone(0), age(0), weight(0.0) { }

//Constructor for Person
Person::person(): surname(0), name(0), phone(0), age(0), weight(0.0) { }

I keep getting all the weird errors that you can find in my compile log. I'm running Dev C++ on Windows XP.

Thanx:cheesy:
Steven

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  • Latest Post Latest Post by Dave Sinkula

Dani AI

Generated

Quick diagnosis: the compiler errors come from a name/signature mismatch and a bad initializer. As noted, C++ is case-sensitive. In ’s header a constructor was declared with the wrong identifier (lowercase) so the compiler treats it as a malformed member declaration. That explains the "ISO C++ forbids declaration ... with no type" and the "only constructors take base initializers" messages: the compiler thinks those are ordinary functions, not constructors, so the initializer lists are illegal.

Concrete fixes and common pitfalls:

  • Make the constructor name exactly the same as the class: Person, no return type. Declarations and definitions must match exactly (name, parameter types, const/ref qualifiers).
  • Don’t initialize std::string members with 0 (null). Use "", std::string(), or let the member default-construct.
  • If a constructor parameter uses std::ifstream in the header, include <fstream> (or accept a std::istream& instead) so the type is known.
  • Prefer const std::string& for string parameters; pass int and double by value rather than by non-const reference unless there’s a reason.

Minimal corrected example (header + definitions):

// in header: include <fstream> if using std::ifstream
class Person {
public:
    Person(const std::string& surname, const std::string& name,
           const std::string& phone, int age, double weight);
    Person(std::istream& in);
private:
    std::string surname, name, phone;
    int age;
    double weight;
};
Person::Person(const std::string& s, const std::string& n,
               const std::string& p, int a, double w)
  : surname(s), name(n), phone(p), age(a), weight(w) { }

Person::Person(std::istream& in)
  : surname(), name(), phone(), age(0), weight(0.0) { /* read from in */ }

Quick troubleshooting checklist: fix the constructor name case first, then make signatures identical between header and implementation, add the proper include for stream types, and rebuild with warnings enabled (e.g., -Wall) to catch remaining problems.

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Member Avatar for V1RuZ

Oh Yeah, and here's my compiler log...

Compiler: Default compiler
Building Makefile: "C:\Documents and Settings\Steven\Desktop\CTI\C++ Unit 3\Finished Project\Makefile.win"
Executing make...
make.exe -f "C:\Documents and Settings\Steven\Desktop\CTI\C++ Unit 3\Finished Project\Makefile.win" all
g++.exe -c person.cpp -o person.o -I"C:/Dev-Cpp/lib/gcc/mingw32/3.4.2/include" -I"C:/Dev-Cpp/include/c++/3.4.2/backward" -I"C:/Dev-Cpp/include/c++/3.4.2/mingw32" -I"C:/Dev-Cpp/include/c++/3.4.2" -I"C:/Dev-Cpp/include"

In file included from person.cpp:8:
person_header.h:26: error: ISO C++ forbids declaration of `person' with no type
person.cpp:68: error: ISO C++ forbids declaration of `person' with no type
person.cpp:68: error: prototype for `int Person::person(std::ifstream&)' does not match any in class `Person'
person_header.h:26: error: candidate is: int Person::person(std::string&, std::string&, std::string&, int&, double&)
person.cpp: In member function `int Person::person(std::ifstream&)':
person.cpp:68: error: only constructors take base initializers
person.cpp: At global scope:
person.cpp:71: error: ISO C++ forbids declaration of `person' with no type
person.cpp:71: error: prototype for `int Person::person()' does not match any in class `Person'
person.cpp:68: error: candidates are: int Person::person(std::ifstream&)
person_header.h:26: error: int Person::person(std::string&, std::string&, std::string&, int&, double&)
person.cpp: In member function `int Person::person()':
person.cpp:71: error: only constructors take base initializers

make.exe: *** [person.o] Error 1

Execution terminated

Member Avatar for V1RuZ

Oh yeah, the error on line 26 occurs in the header and 68 and 71 occur in the definition of the functions

Member Avatar for Dave Sinkula

Remeber that C++ is case-sensitive (uppercase and lowercase matter).

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