Value Categories (L-Values and R-Values)

Accepting L-value References to Const

Why should we pass by const l-value reference when we don't intend to modify the object?

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Passing by const l-value reference is preferred when we don't intend to modify the object for a couple of reasons:

  1. Performance: Passing by reference avoids the overhead of copying the object, which can be significant for large objects or when the function is called frequently. By using a const reference, we indicate that we won't modify the object, allowing the compiler to optimize the code accordingly.
  2. Const-correctness: By declaring the parameter as const, we explicitly state our intention not to modify the object. This makes our code more self-documenting and helps prevent accidental modifications.

Here's an example:

#include <iostream>

void PrintValue(const int& value) {
  std::cout << "Value: " << value << "\n";
}

int main() {
  int x = 42;
  PrintValue(x);  // Passing an l-value
  PrintValue(10); // Passing an r-value
}

In this case, PrintValue accepts a const l-value reference, allowing it to be called with both l-values and r-values efficiently, without modifying the passed object.

Answers to questions are automatically generated and may not have been reviewed.

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