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Student Grade Calculator

Part of the Fundamentals section of Coddy's Rust journey — lesson 75 of 75.

Challenge

Easy

Create a function named calculate_average_grade that takes an array of integers (representing student grades) of length 8 as input and returns the average grade as a string. The method should do the following:

Calculate the sum of all grades in the array.
Calculate the average grade by dividing the sum by the number of grades.
Determine the letter grade based on the average:
- A (Excellent): 90-100
- B (Good): 80-89
- C (Satisfactory): 70-79
- D (Needs Improvement): 60-69
- F (Failed): Below 60
Print the result using the following format: Average grade: [The result] - [Letter Grade] and format the result to two decimal places.

Try it yourself

use std::io;
use std::convert::TryInto;


fn calculate_average_grade(grades: [i32; 8]) -> String {
    // Write your code below
    
}
fn main() {
    let mut input_str_arr = String::new();
    io::stdin().read_line(&mut input_str_arr).unwrap();
    let arr: [i32; 8] = input_str_arr.trim().split(',').map(|s| s.parse::<i32>().unwrap()).collect::<Vec<i32>>().try_into().unwrap();
    let res = calculate_average_grade(arr);
    println!("{}", res);
}

All lessons in Fundamentals

1Introduction

Rust Hello World!Comments Basic Program Structure

4Operators Part 1

Arithmetic Operators Modulo Operator Arithmetic Shortcuts Comparison Operators String Comparison

7Basic IO

Printing to Console Reading User Input Recap - Till 120 Recap - True or False

10Variable Bindings

Scope Shadowing Part 1 Variable Binding Shadowing Part 2

13Arrays Continued

Mutable Reference Arrays Array Methods Recap - Product Array Recap - Reversed Array Better Print

16Final Projects

Number Pattern Pattern FinderStudent Grade Calculator

2Variables Part 1

Numbers Char String Boolean Mutable Variables

5Operators Part 2

Logical Operators Part 1 Logical Operators Part 2 Recap - Simple Logic Logical Operators Part 3

8Calculator App

Welcome Message Getting Numbers

Project lesson

Basic Operations

Project lesson

Formatted Output

Project lesson

11Functions

Declaring Functions Parameters and Arguments Return Values Multiple Return Values Recap - Sigma Function Recap - Validation Function

14Iterating Over Arrays

Range Guide Enhanced For Loop Borrow In Loop Common Array Operations

3Variables Part 2

Type Declaration Naming Conventions Type Inference Recap - Initialize Variables Type Casting

6Decision Making

If Expressions If-Else Match Statement Recap - If Else Nested If - Else

9Loops

For Over Series While Loop Break Continue Nested Loop Loop Labels Infinite Loop Recap - Dynamic Input

12Arrays Basics

Declaring Arrays Array as Parameter Accessing Elements Modifying Arrays Recap - Pretty Print Array

15String Operations

String Methods format! Macro String Conversion Recap - Format