Creating a Vector

Part of the Logic & Flow section of Coddy's Rust journey — lesson 8 of 66.

Now that you understand what vectors are, let's learn how to create them. Rust provides two primary ways to create a vector, each suited for different situations.

The first method uses Vec::new() to create an empty vector that you can add elements to later:

let mut numbers = Vec::new();

Notice that we use mut because we'll likely want to add elements to this empty vector later. Rust can't always determine the type of an empty vector, so you might need to specify it explicitly:

let mut numbers: Vec<i32> = Vec::new();

The second method uses the vec![] macro to create a vector with initial values:

let numbers = vec![1, 2, 3, 4, 5];

The vec![] macro is more convenient when you know the starting values. Rust can automatically determine the type from the values you provide, so no type annotation is needed. This vector contains five integers and is ready to use immediately.

The vec![] macro also supports a repeat syntax to create a vector filled with the same value a specific number of times:

let zeros = vec![0; 5]; // [0, 0, 0, 0, 0]

The syntax is vec![value; n], where value is the element to repeat and n is how many times to repeat it. This is useful when you need a vector of a known size pre-filled with a default value.

Both approaches create the same type of vector - the choice depends on whether you have initial values or plan to build the vector gradually.

Challenge

Easy

You will receive a number as input representing how many elements a vector should contain. Read the input, convert it to an integer, and create a vector with that many elements, where each element is the number 10.

Requirements:

Read the input and convert it to an integer
Create a vector using the vec![] macro
The vector should contain the specified number of elements
Each element should have the value 10
Print each element on a separate line

Input: A single integer representing the number of elements

Output: Print each element of the vector on a separate line

Cheat sheet

Rust provides two primary ways to create vectors:

Using Vec::new() to create an empty vector:

let mut numbers = Vec::new();

Use mut when you plan to add elements later. You may need to specify the type explicitly:

let mut numbers: Vec<i32> = Vec::new();

Using the vec![] macro to create a vector with initial values:

let numbers = vec![1, 2, 3, 4, 5];

The vec![] macro automatically determines the type from the provided values.

Using the vec![] macro to create a vector with a repeated value:

let numbers = vec![0; 5]; // [0, 0, 0, 0, 0]

The syntax vec![value; n] creates a vector containing value repeated n times.

Try it yourself

use std::io;

fn main() {
    // Read input
    let mut input = String::new();
    io::stdin().read_line(&mut input).expect("Failed to read line");
    let n: usize = input.trim().parse().expect("Invalid input");
    
    // TODO: Write your code below
    // Create a vector with n elements, each having the value 10
    
    
    // Print each element on a separate line
    
}