Constructor’s Parameter Name is Same as Data Member Using Member Initializer List in C++

 

1️⃣ Problem: Name Conflict in Constructor

When the constructor parameter has the same name as the class data member, it creates ambiguity.
✅ Solution: Use Member Initializer List with this-> to differentiate between them.

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2️⃣ Syntax

class ClassName {
private:
    int value;  // Data member

public:
    ClassName(int value) : value(value) {  // No ambiguity
    }
};

✅ The first value is the data member.
✅ The second value is the constructor parameter.

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3️⃣ Example: Resolving Name Conflict

#include <iostream>
using namespace std;

class Student {
private:
    string name;
    int age;

public:
    // Using Member Initializer List to resolve name conflict
    Student(string name, int age) : name(name), age(age) {
        cout << "Name: " << this->name << ", Age: " << this->age << endl;
    }
};

int main() {
    Student s1("Alice", 20);
    Student s2("Bob", 22);

    return 0;
}

🔹 Output

Name: Alice, Age: 20
Name: Bob, Age: 22

✅ Why does this work?
✔ name(name) → The first name refers to the class member, the second name is the parameter.
✔ age(age) → The first age refers to the class member, the second age is the parameter.
✔ this->name ensures clarity in the constructor body.

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4️⃣ Example: Resolving Name Conflict for const Members

#include <iostream>
using namespace std;

class Test {
private:
    const int value;  // Constant data member

public:
    // Using Member Initializer List to initialize const member
    Test(int value) : value(value) {
        cout << "Value = " << this->value << endl;
    }
};

int main() {
    Test obj(100);

    return 0;
}

🔹 Output

Value = 100

✅ Why is this necessary?
✔ const int value must be initialized in the Member Initializer List.
✔ value(value) ensures the constructor parameter assigns the value to the class member.

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5️⃣ Example: Resolving Name Conflict in Inheritance

#include <iostream>
using namespace std;

class Base {
protected:
    int id;

public:
    Base(int id) : id(id) {  // Resolving name conflict
        cout << "Base ID = " << this->id << endl;
    }
};

class Derived : public Base {
private:
    string name;

public:
    Derived(int id, string name) : Base(id), name(name) {  // Resolving conflict
        cout << "Derived Name = " << this->name << endl;
    }
};

int main() {
    Derived obj(101, "John");

    return 0;
}

🔹 Output

Base ID = 101
Derived Name = John

✅ Key Takeaways:
✔ id(id) resolves the conflict in Base class.
✔ name(name) resolves the conflict in Derived class.
✔ Ensures clear and efficient initialization in inheritance.

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6️⃣ Summary

✔ Use Member Initializer List to resolve name conflicts when the constructor parameter matches the data member.
✔ this->memberName ensures clarity when needed inside the constructor.
✔ Required for const and reference members.

Would you like an example with multiple inheritance? 🚀