Pass by value and pass by reference in c++

Question

What is the difference between pass by value and pass by reference in C++, and provide an example demonstrating the implications of each method?

Answer 1

In C++, "pass by value" means passing a copy of the actual parameter to the function, while "pass by reference" involves passing a reference (memory address) to the actual parameter.

Here's a brief example to illustrate the difference:

#include <iostream>

// Pass by value function
void passByValue(int x) {
x = 10;
}

// Pass by reference function
void passByReference(int &y) {
y = 10;
}

int main() {
int num1 = 5;
int num2 = 5;

passByValue(num1);
passByReference(num2);

std::cout << "After pass by value: " << num1 << std::endl; // Output: 5
std::cout << "After pass by reference: " << num2 << std::endl; // Output: 10

return 0;
}

In the example, "passByValue" receives a copy of "num1", so changes made inside the function don't affect the original variable. On the other hand, "passByReference" modifies the actual data by using a reference, leading to changes reflected outside the function