If expressions and boundary decisions

A report labels a mark as meeting the target when it reaches 75. An if expression selects a branch based on a bool condition. Because it can produce a value, you can assign the chosen message instead of printing separately inside each branch.

Write the policy with an inclusive comparison when the threshold itself should qualify. When assigning an if result, both branches must produce compatible types. Else if handles additional decisions, but putting a broad condition first can prevent a narrower one from being reached.

Save the complete source as main.rs in the Rust environment. No standard input is needed.

Rust 2024 · complete program

fn main() {
  let score = 75;
  let message = if score >= 75 { "Target met" } else { "More practice" };
  println!("{message}");
}

Expected output

Target met

Follow the execution

The comparison includes 75, so the first branch produces Target met. Both branch values are string slices, which makes the assignment compatible. Main prints the selected message once.

Try the complete program in the Rust compiler. For tests, Cargo commands and local files, use the specified local environment.

Your task: What does the program print if score becomes 74?

Rust 2024 · complete program

fn main() {
  let score = 75;
  let message = if score >= 75 { "Target met" } else { "More practice" };
  println!("{message}");
}

Worked answer

It prints More practice because 74 does not meet the inclusive threshold of 75. Check 74, 75 and 76 to review the boundary.

Conditions must be bool; a nonzero mark is not implicitly true. Avoid using labels such as failure where a neutral next action better expresses the learning policy. The code implements the chosen rule, not a universal grading standard.

It prints More practice because 74 does not meet the inclusive threshold of 75. Check 74, 75 and 76 to review the boundary. Conditions must be bool; a nonzero mark is not implicitly true.

Further reading: the official Rust Book on if expressions and boundary decisions.