Copy Constructor Implementation
Medium
C++
Classes & Objects
27 views
Problem Statement
Create copy constructor to make deep copy of object. This teaches difference between shallow and deep copy.
Logic: Initialize new object using existing object's data
Logic: Initialize new object using existing object's data
Input Format
No user input.
An object is created and copied using a copy constructor.
An object is created and copied using a copy constructor.
Output Format
Values of original and copied object (show they are independent).
Example
Original object value = 10
Original value = 10 Copied value = 10
Constraints
• Class has a pointer data member
• Deep copy must be done in copy constructor
• Deep copy must be done in copy constructor
Concept Explanation
A shallow copy copies only the pointer address.
A deep copy creates new memory and copies the actual value.
Deep copy avoids two objects sharing the same memory.
A deep copy creates new memory and copies the actual value.
Deep copy avoids two objects sharing the same memory.
Step-by-Step Explanation
1.Create a class with a pointer member (e.g., int* data).
2.Allocate memory for data in the constructor and assign a value.
3.Create a copy constructor that takes another object as parameter.
4.Inside copy constructor:
• Allocate new memory for data.
• Copy the value from the other object’s data.
5.Now both objects have separate memory with same value.
6.Changes in one object do not affect the other.
2.Allocate memory for data in the constructor and assign a value.
3.Create a copy constructor that takes another object as parameter.
4.Inside copy constructor:
• Allocate new memory for data.
• Copy the value from the other object’s data.
5.Now both objects have separate memory with same value.
6.Changes in one object do not affect the other.
Concept Explanation
A shallow copy copies only the pointer address.
A deep copy creates new memory and copies the actual value.
Deep copy avoids two objects sharing the same memory.
A deep copy creates new memory and copies the actual value.
Deep copy avoids two objects sharing the same memory.
Step-by-Step Explanation
1.Create a class with a pointer member (e.g., int* data).
2.Allocate memory for data in the constructor and assign a value.
3.Create a copy constructor that takes another object as parameter.
4.Inside copy constructor:
• Allocate new memory for data.
• Copy the value from the other object’s data.
5.Now both objects have separate memory with same value.
6.Changes in one object do not affect the other.
2.Allocate memory for data in the constructor and assign a value.
3.Create a copy constructor that takes another object as parameter.
4.Inside copy constructor:
• Allocate new memory for data.
• Copy the value from the other object’s data.
5.Now both objects have separate memory with same value.
6.Changes in one object do not affect the other.
Input / Output Format
Input Format
No user input.
An object is created and copied using a copy constructor.
An object is created and copied using a copy constructor.
Output Format
Values of original and copied object (show they are independent).
Constraints
• Class has a pointer data member
• Deep copy must be done in copy constructor
• Deep copy must be done in copy constructor
Examples
Input:
Original object value = 10
Output:
Original value = 10
Copied value = 10
Example Solution (Public)
class Array {
public:
int* data;
int size;
Array(int s) {
size = s;
data = new int[size];
for(int i = 0; i < size; i++) {
data[i] = i + 1;
}
}
Array(const Array& other) {
size = other.size;
data = new int[size];
for(int i = 0; i < size; i++) {
data[i] = other.data[i];
}
}
void display() {
for(int i = 0; i < size; i++) {
cout << data[i] << " ";
}
cout << endl;
}
~Array() {
delete[] data;
}
};
void question6_copy_constructor() {
Array arr1(5);
Array arr2 = arr1;
cout << "Array 1: ";
arr1.display();
cout << "Array 2 (copy): ";
arr2.display();
}
Official Solution Code
class Array {
public:
int* data;
int size;
Array(int s) {
size = s;
data = new int[size];
for(int i = 0; i < size; i++) {
data[i] = i + 1;
}
}
Array(const Array& other) {
size = other.size;
data = new int[size];
for(int i = 0; i < size; i++) {
data[i] = other.data[i];
}
}
void display() {
for(int i = 0; i < size; i++) {
cout << data[i] << " ";
}
cout << endl;
}
~Array() {
delete[] data;
}
};
void question6_copy_constructor() {
Array arr1(5);
Array arr2 = arr1;
cout << "Array 1: ";
arr1.display();
cout << "Array 2 (copy): ";
arr2.display();
}
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