Відповідь:

C++ code:

#include <iostream>

class Number{

private:

int number;

public:

Number();

Number(int);

Number(const Number&);

~Number() = default;

void set_number(int number){this->number = number;}

int get_number(){return this->number;}

int c_digit();

int sum_digit();

};

Number::Number(){

number = 0;

}

Number::Number(int number){

this->number = number;

}

Number::Number(const Number& object){

this->number = object.number;

}

int Number::c_digit(){

int counter = 0;

int num = this->number;

while(num){

 counter++;

 num /= 10;

}

return counter;

}

int Number::sum_digit(){

int sum = 0;

int num = this->number;

while(num){

 sum += num % 10;

 num /= 10;

}

return sum;

}

int main(){

Number obj(2578);

std::cout << "Digit: " << obj.c_digit() << std::endl;

std::cout << "Sum digit = " << obj.sum_digit() << std::endl;

return 0;

}