How to Properly Initialize Constant Data Members in C ?

Initializing Constant Data Members

In C programming, constant data members are used to define values that cannot be modified after initialization. When attempting to initialize a const data member within the class definition, you may encounter errors due to C 's restrictions.

Error Explanation

The compiler error is caused because C prohibits the initialization of const data members within the class definition. This is to prevent multiple definitions of the same data member in different translation units.

Solution: Initialization Outside the Class

To initialize a const data member, it must be defined outside the class definition. This can be achieved using the initializer list in the constructor, as shown below:

#include <iostream>

using namespace std;

class T1 {
  const int t;  // Declaration of const data member

public:

  T1() : t(100)  // Initialization in initializer list
  {
    cout << "T1 constructor: " << t << endl;
  }
};

Initializer List

The initializer list within the constructor initializes the const data member before the class initialization. This allows the value to be assigned before the class object is created.

Further Considerations

It is important to note that initializing a const data member using the initializer list must be done within the constructor, and it cannot be modified later in the program.

The above is the detailed content of How to Properly Initialize Constant Data Members in C ?. For more information, please follow other related articles on the PHP Chinese website!