在类C ++中分配变量的值

Question

Hello I can't find out how to assign values to my variables that I am using in one of my class. I am getting error nonstatic member reference must be relative to a specific object so I am doing something wrong but I cant figure how o make it right.

class Triedenie_cisla{
    public:
        Triedenie_cisla(int *poleHodnot, int ddlzka); 
        int *pole, dlzka;  
        double bubble_time, selection_time, insert_time, quick_time;
        vector<int> mnozina_int;                   
        string vypis_pola();        
        void BubbleSort_int();      
        void SelectionSort_int();
        void InsertSort_int();      
        void QuickSort_int();
};

Then in functions that make sorts, I measure the time and trying to assign the time to variables like that

Triedenie_cisla::insert_time = dif;

What I am doing wrong ? Thanks

Answer 1

You need to find a good book on C++, those are basic things.

nonstatic member reference must be relative to a specific object

means that to modify insert_time you must do it on existing object of class: Triedenie_cisla

Then in functions that make sorts, I measure the time and trying to assign the time to variables like that Triedenie_cisla::insert_time = dif;

you should do it like that:

void Triedenie_cisla::BubbleSort_int() {
   // ....
   insert_time = dif;
   //
}

Answer 2

You have to create an object of your class. Then, assigning values is possible.

Triedenie_cisla obj;
obj.insert_time = dif;

Otherwise, the compiler assumes that you want to change the value of a static variable, ie. a variable that exists once for the whole class. To do so, you would have to state
that insert_time is a static variable. For example:

static double insert_time;

Answer 3

If I understand it well, you wish to set the value of insert_time inside your own sorting function which are already part of the class Triedenie_cisla.

Therefore you just need to do

this->insert_time = dif; 

or even

insert_time = dif; 

would be enough

Answer 4

You can not call a variable/method only using class name unless it is static variable/method of the class. Therefore, solution of your problem is:

Solution-1

First make a object of your class:

Triedenie_cisla object_1 = new Triedenie_cisla() ;

Call the variable using object name.

object_1.insert_time = dif;

Solution-2

You can solve this problem also using static key word in front of insert_time in the class declaration:

static  double bubble_time, selection_time, insert_time, quick_time;