Program error; need advice - c++

Question

Generally I have a class named "person" and its methods, print: to print the data, and is_better_than to find some max numbers. I cannot understand what is the problem. Any advice?
#include <iostream>
#include <string>
#include <math.h>
using namespace std;
class person
{
private:
string name;
double weight;
double height;
public:
person(); //Constructor
bool is_better_than(person best);
void read();
void print();
void operator=(const person& b); //overloading operator
};
person::person()
{
string name = "";
double weight = 0;
double height = 0;
}
void person::print()
{
cout << name << "\nWeight: " << weight << "\nHeight: " << height << "\n";
}
void person::read()
{
cout << "Please enter person's name: ";
getline(cin, this->name);
cout << "Please enter person's weight: ";
cin >> this->weight;
cout << "Please enter person's height: ";
cin >> this->height;
string remainder;
getline(cin, remainder); //clear the buffer
}
bool person::is_better_than(person best)
{
if ((this->weight / pow(this->height,2) >= best.weight / (pow(best.height,2))) || best.weight == 0)
return true;
return false;
}
// iperfortosi telesti =
void person::operator=(const person & b)
{
this->name = b.name;
this->weight = b.weight;
this->height = b.height;
}
int main()
{
person maxBMI;
bool cont = true;
while (cont)
{
person newperson;
newperson.read();
if (newperson.is_better_than(maxBMI))
maxBMI = newperson;
cout << "More data? (y/n) ";
string answer;
getline(cin, answer);
if (answer != "y")
cont = false;
}
cout << "The person with maximum BMI (body mass index) is ";
maxBMI.print();
return 0;
}
Output:
Please enter person's name: Name
Please enter person's weight: 123
Please enter person's height: 123
More data? (y/n) n
The person with maximum BMI (body mass index) is
Weight: 1.7881e-307
Height: 2.0746e-317

Answer 1

Your default constructor does not work because it assigns to local variables and not to class variables. It should look like this:
person::person()
{
name = "";
weight = 0;
height = 0;
}
or better:
person::person() : name(""), weight(0.0), height(0.0) {}
With your default constructor, the class attributes remain uninitialized and the assumption that best.weightis initially zero, does not work.