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C++ programming language
Initialization of class's const data member in C++
A const data member cannot be initialized at the time of declaration or within the member function definition.
To initialize a const data member of a class, follow given syntax:
Declaration
const data_type constant_member_name;
Initialization
class_name(): constant_member_name(value)
{
}
Let's consider the following example/program
#include <iostream>
using namespace std;
class Number
{
private:
const int x;
public:
//const initialization
Number():x(36){}
//print function
void display()
{cout<<"x="<<x<<endl;}
};
int main()
{
Number NUM;
NUM.display();
return 0;
}
x=36
In this program, Number is a class and x is a constant integer data member, we are initializing it with 36.
Here,
Declaration of const data member is:
const int x;
Initialization of const data member is:
Number():x(36){}