Currently, I am trying to implement what I have learned so far: OOP class in C . Here I have two different classes: VehicleInfo and Vehicle. Here down below is my written code:
#include <iostream>
#include <string>
#include <fstream>
#include <math.h>
#define M_PI 3.1416
using namespace std;
class VehicleInfo{
public:
string brand;
bool electric;
int catalogue_price;
float tax_percentage = 0.05;
VehicleInfo(string brand, bool electric, int catalogue_price){
VehicleInfo::brand = brand;
VehicleInfo::electric = electric;
VehicleInfo::catalogue_price = catalogue_price;
}
float compute_tax(){
if (VehicleInfo::electric == true){
tax_percentage = 0.02;
}
return VehicleInfo::catalogue_price * tax_percentage;
}
void print_vehicle_info(){
std::cout << "Brand : " << brand << std::endl;
std::cout << "Payable Tax : " << compute_tax() << std::endl;
}
};
class Vehicle{
public:
string id;
string license_plate;
VehicleInfo vehicle;
Vehicle(string id, string license_plate, VehicleInfo vehicle){
Vehicle::id = id;
Vehicle::license_plate = license_plate;
Vehicle::vehicle = vehicle;
}
string getName(){
return Vehicle::vehicle.brand;
}
int getTax(){
return Vehicle::vehicle.compute_tax();
}
void print_vehicle(){
std::cout << "ID : " << id << std::endl;
std::cout << "License Plate : " << license_plate << std::endl;
std::cout << "Brand : " << getName() << std::endl;
std::cout << "Tax : " << getTax() << std::endl;
}
};
int main(int argc, char const *argv[])
{
cout << endl;
VehicleInfo unit1 = VehicleInfo("Tesla Model 3", true, 60000);
unit1.print_vehicle_info();
Vehicle unit2 = Vehicle("YU2314", "KL0932", unit1);
unit2.print_vehicle();
std::cin.get();
return 0;
}
What I expect from the code is that the attribute 'vehicle' in class Vehicle would initialize using attribute and function 'compute_tax()' from class VehicleInfo. Error code I received showed like this:
cohesion_coupling.cpp: In constructor 'Vehicle::Vehicle(std::__cxx11::string, std::__cxx11::string, VehicleInfo)':
cohesion_coupling.cpp:42:70: error: no matching function for call to 'VehicleInfo::VehicleInfo()'
Vehicle(string id, string license_plate, VehicleInfo vehicle){
^
cohesion_coupling.cpp:17:9: note: candidate: 'VehicleInfo::VehicleInfo(std::__cxx11::string, bool, int)'
VehicleInfo(string brand, bool electric, int catalogue_price){
^~~~~~~~~~~
cohesion_coupling.cpp:17:9: note: candidate expects 3 arguments, 0 provided
cohesion_coupling.cpp:10:7: note: candidate: 'VehicleInfo::VehicleInfo(const VehicleInfo&)'
class VehicleInfo{
^~~~~~~~~~~
cohesion_coupling.cpp:10:7: note: candidate expects 1 argument, 0 provided
cohesion_coupling.cpp:10:7: note: candidate: 'VehicleInfo::VehicleInfo(VehicleInfo&&)'
cohesion_coupling.cpp:10:7: note: candidate expects 1 argument, 0 provided
Any suggestion to improve the code (or perhaps some corrections needed on class practices that I have done) ?
CodePudding user response:
In your Vehicle
constructor, the compiler first has to default-construct all the member variables. Only after that will the code in the constructor run and Vehicle::vehicle = vehicle;
will get called.
So your vehicle
member variable will first get default-constructed and then assigned a value.
But your VehicleInfo
does not have a default constructor, which is the error you're getting.
To get around this, use member initializers like so:
Vehicle(string id, string license_plate, VehicleInfo vehicle) :
id(id),
license_plate(license_plate),
vehicle(vehicle)
{
}