Answer

C. The program outputs: 66

Why? Unlike some languages, Rust doesn’t have Unary operators for incrementing or decrementing variables. Rust deliberately avoids unary increment (++) and decrement (–) operators for several reasons:

Complexity: Unary operators can be confusing due to their dependence on evaluation order. It can be unclear whether the decrement happens before or after the value is used.

Clarity: Explicit expressions like (y -= 1) or (y = y + 1) are more readable and less prone to errors.

Alternatives: Rust often promotes iterators and functional programming approaches, which can achieve similar results without these operators.

Alternative Approach:

Here’s how you can achieve a similar outcome in Rust using explicit decrements:

fn main() {
  let mut y = 6;
  y -= 1;

  println!("{}{}", y, y);
}

This approach is more explicit and avoids the potential confusion of unary operators.