CODEWITHSUNDEEP
c++
Time
Time

Reputation: 65

How to call a function from a class - error "was not in the scope"

This is my program which leads to compilation errors mentioned below:

#include <iostream>
using namespace std;

class weight{
    private:
        float current_weight, diet_weight, num_exercise;
        int num_meal,i;

    public:

        // make users to enter current weight
        void get_curent_weight()
        {
            cout<<"Please enter your current weight: "; 
            cin>>current_weight;
        }
        void enter_data()
        {
            for (i=1; i>7; i++)
            {
                cout<<"Day "<<i<<endl;
                cout<<"--------------"<<endl;
                // Number of Meal(s)
                cout<<"Number of meal(s) you eat today: ";
                cin>>num_meal;
                cout<<endl;
                // Number of Exercise
                cout<<"Number of hour(s) you spent on exercises today: ";
                cin>>num_exercise;
                cout<<endl;
            }
        }
        // output the information
        void information()
        {
            // calculate the final weight
            diet_weight=current_weight+(0.5*num_meal)-(num_exercise/3)*0.5;
            cout<<"Your weight after 7 days diet: "<<diet_weight<<endl;
        }
};

int main(){

    get_curent_weight();
    enter_data();
    information();
    return(0);
}

I get the following compilation errors 

error: 'get_curent_weight' was not declared in this scope
error: 'enter_data' was not declared in this scope
error: 'information' was not declared in this scope

It seems I call the function in wrong way.... Thank you for reading my question, as a beginner of C++, I appreciate it. :))

Upvotes: 1

Views: 60

Answers (2)

BusyProgrammer
BusyProgrammer

Reputation: 2791

A class can be called a blueprint; it's functions can only be implemented on an object of the class that function belongs to. That function cannot be called as a standalone. To resolve your error, you need to declare an object in your main() function with the data type weight and then call the function with that created object. An example of such would be like:

weight object_name;

object_name.get_curent_weight();
object_name.enter_data();
object_name.information();

Alternatively, you can take the functions out of the class; this way, they can be used without an object of class weight. This will take a lot more effort over the first choice I suggested.

Upvotes: 0

Emil Laine
Emil Laine

Reputation: 42828

You need to create an instance of the class, and call the member functions on that instance:

int main() {
    weight my_weight;
    my_weight.get_curent_weight();
    my_weight.enter_data();
    my_weight.information();
    return 0;
}

Upvotes: 1

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