Rust Array Sum Guide

Rust Arrays: Exercise-4 with Solution

Write a Rust program to create an array of integers with size 7 and initialize it with random values. Calculate and print the sum of all the elements in the array.

Sample Solution:

Rust Code:

use rand::Rng; // Import the rand crate to generate random numbers

fn main() {
    // Define an array with a size of 7 and initialize it with random values
    let mut arr: [i32; 7] = [0; 7]; // Declare an array of type i32 (integer) with a size of 7 and initialize it with zeros
    let mut rng = rand::thread_rng(); // Initialize the random number generator
    
    for i in 0..7 { // Iterate over each index of the array
        arr[i] = rng.gen_range(1..101); // Generate a random integer between 1 and 100 and assign it to the current index
    }

    // Calculate the sum of all elements in the array
    let sum: i32 = arr.iter().sum(); // Use the sum() method on an iterator over the array elements to calculate the sum

    // Print the sum of all elements in the array
    println!("Sum of all elements of the said random numbers: {}", sum); // Print the sum to the console
}

Output:

Sum of all elements of the said random numbers: 294

Explanation:

Here is a brief explanation of the above Rust code:

• use rand::Rng;: This line imports the rand::Rng trait from the "rand" crate, which provides functions for generating random numbers.
• fn main() {: This line defines the main function, which is the entry point of the Rust program.
• let mut arr: [i32; 7] = [0; 7];: This line declares an array named 'arr' of type 'i32' (integer) with a size of 7 and initializes it with zeros.
• let mut rng = rand::thread_rng();: This line initializes the random number generator by creating a thread-local generator.
• for i in 0..7 { ... }: This line starts a for loop that iterates over each index of the array arr.
• arr[i] = rng.gen_range(1..101);: This line generates a random integer between 1 and 100 using the "gen_range()" method of the random number generator 'rng', and assigns it to the current index 'i' of the array 'arr'.
• let sum: i32 = arr.iter().sum();: This line calculates the sum of all elements in the array 'arr' using the sum() method on an iterator over the array elements.
• println!("Sum of all elements: {}", sum);: This line prints the sum of all elements in the array to the console.

Rust Code Editor:

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