Wrote program for Day 65

README.md

@@ -111,7 +111,7 @@ We encourage you to share your progress and ask questions in the Discussions sec
 | Day #62       | [Funny Plant](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-09/Day-62_Funny-Plant)                           | :white_check_mark:      |
 | Day #63       | [The Rabbit Problem](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-09/Day-63_The-Rabbit-Problem)                    | :white_check_mark:      |
 | Day #64       | [First Recurring Character](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-10/Day-64_First-Recurring-Character)             | :white_check_mark:      |
-| Day #65       | [ISBN Validator](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-10/Day-65_ISBN-Validator)                        | :white_large_square:      |
+| Day #65       | [ISBN Validator](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-10/Day-65_ISBN-Validator)                        | :white_check_mark:      |
 | Day #66       | [ISBN Generator](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-10/Day-66_ISBN-Generator)                        | :white_large_square:      |
 | Day #67       | [Color Maze](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-10/Day-67_Color-Maze)                            | :white_large_square:      |
 | Day #68       | [Clarence The Slow Typist](https://github.com/LiveGray/100-Days-Of-Rust/tree/main/Week-10/Day-68_Clarence-The-Slow-Typist)              | :white_large_square:      |

Week-10/Day-65_ISBN-Validator/day65/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "day65"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

Week-10/Day-65_ISBN-Validator/day65/src/lib.rs

@@ -0,0 +1,19 @@
+pub fn isbn_validator(digits: &str) -> Result<bool, String> {
+    if digits.len() != 10 {
+        return Err("Invalid length for the ISBN".to_owned());
+    }
+    let mut val = 0;
+    for (i, digit) in digits[..digits.len() - 1].chars().enumerate() {
+        if !digit.is_ascii_digit() {
+            return Err("Only digits allowed".to_owned());
+        }
+        val += (digit as u8 - b'0') * (10u8 - i as u8);
+    }
+    let digit = digits.chars().last().unwrap();
+    if digit == 'X' {
+        val += 10;
+    } else {
+        val += digit as u8 - b'0';
+    }
+    Ok(val % 11 == 0)
+}

Week-10/Day-65_ISBN-Validator/day65/src/main.rs

@@ -0,0 +1,20 @@
+use std::{
+    io::{self, Write},
+    process::exit,
+};
+
+use day65::isbn_validator;
+
+fn main() {
+    let mut buffer = String::new();
+    print!("Insert a ISBN to check if it's valid: ");
+    io::stdout().flush().unwrap();
+    io::stdin().read_line(&mut buffer).unwrap();
+    match isbn_validator(buffer.trim()) {
+        Ok(x) => println!("The ISBN is {}valid", if x { "" } else { "not " }),
+        Err(e) => {
+            eprintln!("{e}");
+            exit(1);
+        }
+    }
+}

Week-10/Day-65_ISBN-Validator/day65/tests/examples.rs

@@ -0,0 +1,35 @@
+#[cfg(test)]
+mod examples {
+    use day65::isbn_validator;
+
+    #[test]
+    fn example1() {
+        assert!(isbn_validator("0747532699").unwrap());
+    }
+
+    #[test]
+    fn example2() {
+        assert!(isbn_validator("123456789X").unwrap());
+    }
+
+    #[test]
+    fn example3() {
+        assert!(!isbn_validator("1234567890").unwrap());
+    }
+
+    #[test]
+    fn example4() {
+        assert_eq!(
+            isbn_validator("abcdefghil"),
+            Err("Only digits allowed".to_owned())
+        )
+    }
+
+    #[test]
+    fn example5() {
+        assert_eq!(
+            isbn_validator("123"),
+            Err("Invalid length for the ISBN".to_owned())
+        )
+    }
+}