Vectors

Additional Resources

• Rust Programming Tutorial #24 - Vectors

Exercises

Pushing

// Complete the function to make the program execute successfully.

fn append(nums, num) {
}

fn main() {
    let mut nums = vec![1, 2, 5, 6];
    append(&mut nums, 8);
    append(&mut nums, 3);
    assert_eq!(nums.len(), 6);
}

fn append(nums: &mut Vec<i32>, num: i32) {
  nums.push(num);
}

fn main() {
  let mut nums = vec![1, 2, 5, 6];
  append(&mut nums, 8);
  append(&mut nums, 3);
  assert_eq!(nums.len(), 6);
}

Removing

// Complete the function to make the program execute successfully.

fn remove_if_odd(nums, index) {
    if index > nums.len() {
        println!("Index out of bounds");
        return;
    }
}

fn main() {
    let mut nums = vec![1, 2, 6, 9];
    let nums_ref = &mut nums;
    remove_if_odd(nums_ref, 0);
    remove_if_odd(nums_ref, 1);
    remove_if_odd(nums_ref, nums_ref.len() - 1);
    assert_eq!(nums.len(), 2);
}

fn remove_if_odd(nums: &mut Vec<i32>, index: usize) {
  if index > nums.len() {
      println!("Index out of bounds");
      return;
  }
  if nums[index] % 2 == 1 {
      nums.remove(index);
  }
}

fn main() {
  let mut nums = vec![1, 2, 6, 9];
  let nums_ref = &mut nums;
  remove_if_odd(nums_ref, 0);
  remove_if_odd(nums_ref, 1);
  remove_if_odd(nums_ref, nums_ref.len() - 1);
  assert_eq!(nums.len(), 2);
}

Fetching

// Fix the code so that it compiles.

fn main() {
    let names = vec!["Alice", "Bob", "Cindy"];
    let index = 2;
    if names.get(index) {
        println!("{name} is present at index {index}");
    } else {
        println!("invalid index {index}");
    }
}

fn main() {
  let names = vec!["Alice", "Bob", "Cindy"];
  let index = 2;
  if let Some(name) = names.get(index) {
      println!("{name} is present at index {index}");
  } else {
      println!("invalid index {index}");
  }
}

Iterating

// Fix the code so that it compiles.

struct Student {
    name: String,
    marks: u8,
}

impl Student {
    fn new(name: &str, marks: u8) -> Self {
        Self {
            name: name.to_string(),
            marks,
        }
    }
}

fn main() {
    let students = vec![
        Student::new("Harry", 75),
        Student::new("Hermoine", 99),
        Student::new("Ron", 60),
    ];
    let mut grades = Vec::new();
    for student in students {
        if student.marks > 80 {
            grades.push('A');
        } else if student.marks > 60 {
            grades.push('B');
        } else {
            grades.push('C');
        }
    }
    for i in 0..grades.len() {
        println!("{} got {}!", students[i].name, grades[i]);
    }
}

struct Student {
  name: String,
  marks: u8,
}

impl Student {
  fn new(name: &str, marks: u8) -> Self {
      Self {
          name: name.to_string(),
          marks,
      }
  }
}

fn main() {
  let students = vec![
      Student::new("Harry", 75),
      Student::new("Hermoine", 99),
      Student::new("Ron", 60),
  ];
  let mut grades = Vec::new();
  for student in students.iter() {
      if student.marks > 80 {
          grades.push('A');
      } else if student.marks > 60 {
          grades.push('B');
      } else {
          grades.push('C');
      }
  }
  for i in 0..grades.len() {
      println!("{} got {}!", students[i].name, grades[i]);
  }
}

Iterating & mutation

// Fix the code so that it compiles.

struct Student {
    name: String,
    marks: u8,
    grade: char,
}

impl Student {
    fn new(name: &str, marks: u8) -> Self {
        Self {
            name: name.to_string(),
            marks,
            grade: 'X',
        }
    }
}

fn main() {
    let students = vec![
        Student::new("Harry", 75),
        Student::new("Hermoine", 99),
        Student::new("Ron", 60),
    ];
    for student in students {
        student.grade = if student.marks > 80 {
            'A'
        } else if student.marks > 60 {
            'B'
        } else {
            'C'
        };
    }
    for student in students {
        println!("{} got {}!", student.name, student.grade);
    }
}

struct Student {
  name: String,
  marks: u8,
  grade: char,
}

impl Student {
  fn new(name: &str, marks: u8) -> Self {
      Self {
          name: name.to_string(),
          marks,
          grade: 'X',
      }
  }
}

fn main() {
  let mut students = vec![
      Student::new("Harry", 75),
      Student::new("Hermoine", 99),
      Student::new("Ron", 60),
  ];
  for student in students.iter_mut() {
      student.grade = if student.marks > 80 {
          'A'
      } else if student.marks > 60 {
          'B'
      } else {
          'C'
      };
  }
  for student in students {
      println!("{} got {}!", student.name, student.grade);
  }
}