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All LessonsFree Lessons (5)

Welcome to Begin Rust

Introduction Instructions

Hello World and variables

Hello World What Does That Mean?Interpolation Variables More Math!Multiple Variables and Shadowing Types Summary Exercises

Anatomy of Rust

Introduction Pairing and Nesting Layout Comments Expressions, Values, and Types Variables, Again Effects Versus Results Blocks and Statements Summary Exercises

Functions

Hello World, Again Function Parameters Function Results Multiple Parameters Variable and Parameter Scope Anatomy of a Function Calling Functions Is main Special?Summary Exercises

Booleans

Comparison Operators

Functions Returning Booleans

The Not Operator

Not-ing Other Comparison Operators

Conditionals

Hello If A Note on Semicolons Else Else If Evaluating to Values Factorial and Recursion Summary Exercises

Mutable variables and while loops

While Expressions/Loops Failed Attempt: Shadowing Almost Correct: Assignment More Than Once!Counting Sum Nested Loops Mutation and Shadowing Let Without Assignment Summary Exercises

Structs and ownership

All This Fruit!Struct Call Another Function Ownership and Moving Copy Values Make a Copy Move Out!Increasing Fruit Upper and Lower Case Summary Exercises

References

Borrow Mutable References What's In a Reference?Deref Lifetimes of References Mutating and Borrowing Multiple References Single Mutable Reference Mutable to Immutable Summary Exercises

Methods

Hello Method Calls!Type Inference Side Note: Underscores in Numbers Negative Numbers are Annoying Hello Method Implementations!Methods by Reference Static Methods The Self Type Method Call Chaining Summary Exercises

Strings

Bits, Bytes, and Memory Dynamically Sized Types Program Memory Lifetimes of String Literals Owned Strings The Type of Owned Strings Moving Strings Borrowing a String A Better Person The format! Macro Freeing Summary Exercises

Arrays, Vecs, and slices

Arrays Indexing Slices The Relation to String Slices Vec Slicing a Slice Summary Exercises

Type parameters

Parameterized Structs Parameterized Functions Parameterized impl Blocks Turbofish!Summary Exercises

Traits

Double Double Trait Bounds Parameterized Fruit Display Clone and Derive Copy and Marker Traits Debug Partial Equal, Partial Order Using Traits From std Multiple Bounds Associated Types Summary Exercises

Enums

Get Me a Job Using Variants Pattern Matching Commas and Braces More Teachers Methods for Enums Optional Results Capturing with Match Summary Exercises

Iterators and for loops

Count to 10 Iterators Inclusive Range Expressions Iterating Over a Vec IntoIterator The Rule of 3 Arrays and Slices Iterating on Strings Generic Iterator Functions Summary Exercises

Early exit

Time for a Break Go On...Replacing For With While Returning The Favor Salaries Let Me Ask You a Question Failing With Style Errors in main Summary Exercises

What’s next?

Install Rust on Your Local Machine Do More Exercises Get Involved Thank you!

The Ultimate Guide to Rust Programming/

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And/Or

And/Or

We'll cover the following...

Let’s say I’m selling movie tickets and we give a discount to people under 18, as well as to people 65 and older. I’d like to write a function gets_discount(). I can state the requirement in almost-code as age < 18 OR age >= 65. Unfortunately, that OR isn’t real Rust code. Instead, it’s time to introduce the or operator, which is two pipes || (hold shift and hit the backslash key on most keyboards).

Exercise

Implement the gets_discount function correctly to make this program pass.

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fn gets_discount(age: u32) -> bool {
    unimplemented!() // replace this!
}
fn main() {
    // Kids
    assert_eq!(gets_discount(7), true);
    assert!(gets_discount(8));
    assert!(gets_discount(17));
    // Adults
    assert_eq!(gets_discount(18), false);
    assert!(!gets_discount(30));
    assert!(!gets_discount(64));
    // Seniors
    assert!(gets_discount(65));
    assert!(gets_discount(70));
    println!("Success!");
}

The or operator is binary, so it takes two values. I’ll explain this the same way I explained or above.

If either or both values are true, it evaluates ...