Change the value of member variable of a const function in C++
In this tutorial, we will learn to change the value of member variable of a const function in c++. For this, we will use the mutable keyword in C++.
The keyword mutable is mainly used to allow a particular data member of const object to be modified
Check Here: mutable
Approach:
- Firstly, create a class in which member variable is to be declared.
- Now, Declare member variable as mutable by using mutable keyword.
- In the setValue() function, we will change the value of member variable.
- Also, create printNumber() function to print the value of the variable.
The implementation of the above approach is given below:
#include <iostream> using namespace std; // creating example class class Example { private: mutable int number; public: // const function is changing the value of the number void setValue(int value) const{ number = value; number++; } // it will print the value of the number void printNumber() { cout << "value of number is: " << number << endl; } }; int main() { Example obj; // creating the object obj.setValue(12); // setting value to 12 obj.printNumber(); // printing the number }
Output:
value of number is: 13
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