diff --git a/exercise/e_control_flow/Cargo.toml b/exercise/e_control_flow/Cargo.toml index 133a536d..56a83ce3 100644 --- a/exercise/e_control_flow/Cargo.toml +++ b/exercise/e_control_flow/Cargo.toml @@ -1,5 +1,5 @@ [package] -name = "d_control_flow_strings" +name = "e_control_flow" version = "0.1.0" edition = "2021" diff --git a/exercise/e_control_flow/src/main.rs b/exercise/e_control_flow/src/main.rs index 90fb6733..212732cf 100644 --- a/exercise/e_control_flow/src/main.rs +++ b/exercise/e_control_flow/src/main.rs @@ -1,57 +1,67 @@ // Silence some warnings so they don't distract from the exercise. -#![allow(dead_code, unused_mut, unused_variables)] +#![allow(unused_mut, unused_variables)] fn main() { - // This collects any command-line arguments into a vector of Strings. - // For example: + // 1. Use an unconditional `loop` to count how many times we can double `bunnies` until there + // are over 500 bunnies. (Hint: The answer is 8 times) // - // cargo run apple banana - // - // ...produces an 'args' variable with the equivalent of: - // - // vec!["apple".to_string(), "banana".to_string()] - let args: Vec = std::env::args().skip(1).collect(); - - // This consumes the `args` vector to iterate through each String - for arg in args { - // 1a. Your task: handle the command-line arguments! - // - // - If arg is "sum", then call the sum() function - // - If arg is "double", then call the double() function - // - If arg is anything else, then call the count() function, passing "arg" to it. - - // 1b. Now try passing "sum", "double" and "bananas" to the program by adding your argument - // after "cargo run". For example "cargo run sum" - } -} - -fn sum() { - let mut sum = 0; - // 2. Use a "for loop" to iterate through integers from 7 to 23 *inclusive* using a range - // and add them all together (increment the `sum` variable). Hint: You should get 255 - // Run it with `cargo run sum` - - println!("The sum is {}", sum); -} + // Inside the loop: + // - Add 1 to `count` + // - Multiply `bunnies` by 2 + // - If `bunnies` is larger than 500, break out of the loop. -fn double() { let mut count = 0; - let mut x = 1; - // 3. Use a "while loop" to count how many times you can double the value of `x` (multiply `x` - // by 2) until `x` is larger than 500. Increment `count` each time through the loop. Run it - // with `cargo run double` Hint: The answer is 9 times. + let mut bunnies = 2; + + // (write your `loop` here) println!( - "You can double x {} times until x is larger than 500", + "Bunnies doubled {} times before there were more than 500", count ); -} -fn count(arg: String) { - // Challenge: Use an unconditional loop (`loop`) to print `arg` 8 times, and then break. - // You will need to count your loops, somehow. Run it with `cargo run bananas` + // 2. Use a `for` loop to iterate through integers from 7 to 23 *inclusive* using a range + // and add them all together (add each value to the `sum` variable). Hint: You should get 255 + + let mut sum = 0; + + // (write the `for` loop here) + + println!("The sum is {}", sum); + + // 3. Use a `while` loop to create a vector containing the first 12 multiples of 5. + // + // The loop should continue until `fives.len()` returns 12. + // + // Each time through the loop, call `fives.push( ... )` to push `current_five` onto the vector, + // and then add 5 to `current_five`. + + let mut fives: Vec = vec![]; + let mut current_five = 5; + + // (write the `while` loop here) + + println!("Here are the first 12 multiples of 5: {:?}", fives); + + // 4. Use `if`, `else if` and `else` inside the `for` loop below to do the following: // - // print!("{} ", arg); // Execute this line 8 times, and then break. `print!` doesn't add a newline. + // - If the number is 0, then add 7 to `total` + // - If the number is 1 or 2 then add 30 to `total` + // - If the number is anything else, subtract 5 from `total` + // + // Hint: The total should be 52 - println!(); // This will output just a newline at the end for cleanliness. + let mut total = 0; + let numbers = vec![0, 1, 2, 3, 4, 5]; + for number in numbers { + // (write your `if/else` expression here) + } + + println!("The total is {}", total); + + // Challenge: Change the implementation of your answers to #1-#3 as follows: + // + // - Change #1 to use `while` + // - Change #2 to use `loop` + // - Change #3 to use `for` and a range (multiply the range value by 5 inside your loop before }