Rust Cheat Sheet

{ // The scope limited to this braces let a\_number = 1; } println!("{a\_number}"); 

This will produce error as the scope of the variable a_number ends at the braces

let mut borrow = 10; let deref = &mut borrow; println!("{}", *deref); 

De-referencing in rust can be done using the * operator

let mut foo = 4; let mut borrowed\_foo = &foo; println!("{borrowed\_foo}"); 

let mut bar = 3; let mut mutable\_borrowed\_bar = &mut bar; println!("{mutable\_borrowed\_bar}"); 

Here borrowed value borrows the value from value one using & operator.

let a\_int = 90; // int // int to float let mut type\_cast = (a_int as f64); 

let orginal: char = 'I'; // char to int => 73 let type\_casted: i64 = orginal as i64; 

To perform type-casting in Rust one must use the as keyword.

fn main(){ let mut arr:[i32; 5] = [2,4,6,8,10]; multiply(arr); println!("The array is : {:?}", multiply(arr)); } fn multiply (mut arr: [i32 ; 5]) -> [i32 ; 5]{ arr[2] = 90; for mut i in 0..5 { arr[i] = arr[i] * arr[2]; } return arr; } 

fn main(){ let mut array: [i32 ; 5] = [1,2,3,4,6]; print\_arrays(array); println!("The elements: {array:?}"); } fn print\_arrays(mut array:[i32; 5]) { array[0] = 89; array[1] = 90; array[2] = 91; array[3] = 92; array[4] = 93; println!("The elements: {array:?}"); } 

fn main(){ let (mut radius, mut pi) = (3.0, 3.14); let(area, _perimeter) = calculate ( &mut radius, &mut pi ); println!("The area and the perimeter of the circle are: {area} & {\_perimeter}"); } fn calculate(radius : &mut f64, pi: &mut f64) -> (f64, f64){ let perimeter = 2.0 * *pi * *radius; let area = *pi * *radius * *radius; return (area, perimeter); } 

fn main(){ let mut by\_ref = 3; // => 3 power\_of\_three(&mut by_ref); println!("{by\_ref}"); // => 9 } fn power\_of\_three(by_ref: &mut i32){ // de-referencing is important *by_ref = *by_ref * *by_ref; println!("{by\_ref}"); // => 9 } 

fn main() { let x:u32 = 10; let y:u32 = 20; // => 200 println!("Calc: {}", cal\_rect(x, y)); } fn cal\_rect(x:u32, y:u32) -> u32 { x * y } 

fn print\_message(){ println!("Hello, QuickRef.ME!"); } fn main(){ //Invoking a function in Rust. print\_message(); } 

for (v, c) in (0..10+1).enumerate(){ println!("The {c} number loop"); if v == 9{ println!("Here we go continue?"); continue; } println!{"The value of v is : {v}"}; } 

let mut i = 1; loop { println!("i is {i}"); if i > 100 { break; } i *= 2; } 

loop { println!("hello world forever!"); } 

The infinite loop indicated.

let mut check = 0; while check < 11{ println!("Check is : {check}"); check+=1; println!("After incrementing: {check}"); if check == 10{ break; // stop while } } 

for mut i in 0..15 { i-=1; println!("The value of i is : {i}"); } 

let nested\_conditions = 89; if nested_conditions == 89 { let just\_a\_value = 98; if just_a_value >= 97 { println!("Greater than 97"); } } 

let day\_of\_week = 2; match day_of_week { 1 => { println!("Its Monday my dudes"); }, 2 => { println!("It's Tuesday my dudes"); }, 3 => { println!("It's Wednesday my dudes"); }, 4 => { println!("It's Thursday my dudes"); }, 5 => { println!("It's Friday my dudes"); }, 6 => { println!("It's Saturday my dudes"); }, 7 => { println!("It's Sunday my dudes"); }, _ => { println!("Default!") } }; } 

let mut arr1:[i64 ; 3] = [1,2,3]; if let[1,2,_] = arr1{ println!("Works with array"); } let mut arr2:[&str; 2] = ["one", "two"]; if let["Apple", _] = arr2{ println!("Works with str array too"); } 

let tuple\_1 = ("India", 7, 90, 90.432); if let(_, 7, 9, 78.99) = tuple_1{ println!("Works with tuples too"); } let tuple\_2 = ( 9, 7, 89, 12, "Okay"); if let(9, 7,89, 12, blank) = tuple_2 { println!("Everything {blank} mate?"); } let tuple\_3 = (89, 90, "Yes"); if let(9, 89, "Yes") = tuple_3{ println!("Pattern did match"); } else { println!("Pattern did not match"); } 

let foo = 12; let bar = 13; if foo == bar { println!("foo is equal to bar"); } else if foo < bar { println!("foo less than bar"); } else if foo != bar { println!("foo is not equal to bar"); } else { println!("Nothing"); } 

let case3 = 8; let case4 = 9; if case3 >= case4 { println!("case3 is better than case4"); } else { println!("case4 is greater than case3"); } 

let case1: i32 = 81; let case2: i32 = 82; if case1 < case2 { println!("case1 is greater than case2"); } 

let mut k = 9; let mut l = k; 

| !c | c is false (NOT) |

let (c, d) = (true, false); let and = c && d; // => false let or = c || d; // => true let not = !c; // => false 

| g >> h | Binary shift right |

let (g, h) = (0x1, 0x2); let bitwise\_and = g & h; // => 0 let bitwise\_or = g | h; // => 3 let bitwise\_xor = g ^ h; // => 3 let right\_shift = g >> 2; // => 0 let left\_shift = h << 4; // => 32 

| a * b | a is multiplied with b |

let (a, b) = (4, 5); let sum: i32 = a + b; // => 9 let subtractions: i32 = a - b; // => -1 let multiplication: i32 = a * b; // => 20 let division: i32 = a / b; // => 0 let modulus: i32 = a % b; // => 4 

| e >= f | e is greater or equal to f |

let (e, f) = (1, 100); let greater = f > e; // => true let less = f < e; // => false let greater\_equal = f >= e; // => true let less\_equal = e <= f; // => true let equal\_to = e == f; // => false let not\_equal\_to = e != f; // => true 

let mut hi = String::from("Hey there..."); hi.push\_str("How are you doing??"); // => Hey there...How are you doing?? println!("{hi}"); 

let mut half\_text = String::from("Hal"); half_text.push('f'); // => Half 

let name = String::from("ElementalX"); name.contains("Element") // => true 

Checks if the substring is contained inside the original string or not.

let rand = String::from("Random String"); rand.capacity() // => 13 

Calculates the capacity of the string in bytes.

// Creating an empty string object let my\_string = String::new; // Converting to a string object let S\_string = a_string.to\_string() // Creating an initialized string object let lang = String::from("Rust"); println!("First language is {lang}"); 

let tuple = (1, 'A' , "Cool", 78, true); 

let some\_vector = vec![1,2,3,4,5]; 

A vector is declared using the vec! macro.

let mut array: [ i64; 4] = [1,2,3,4]; let mut slices: &[i64] = &array[0..3] // Lower range is inclusive and upper range is exclusive println!("The elements of the slices are : {slices:?}"); 

let mut array: [i32 ; 3] = [2,6,10]; array[1] = 4; array[2] = 6; 

Use the mut keyword to make it mutable.

 j0 j1 j2 j3 j4 j5 ┌────┬────┬────┬────┬────┬────┐ i0 | 1 | 2 | 3 | 4 | 5 | 6 | ├────┼────┼────┼────┼────┼────┤ i1 | 6 | 5 | 4 | 3 | 2 | 1 | └────┴────┴────┴────┴────┴────┘ 

let array: [[i64; 6] ;2] = [ [1,2,3,4,5,6], [6,5,4,3,2,1]]; 

┌─────┬─────┬─────┬─────┬─────┬─────┐ | 92 | 97 | 98 | 99 | 98 | 94 | └─────┴─────┴─────┴─────┴─────┴─────┘ 0 1 2 3 4 5 

let array: [i64; 6] = [92,97,98,99,98,94]; 

let community\_name = "AXIAL"; let no\_of\_members: &str = "ten"; println!("The name of the community is {community\_name} and it has {no\_of\_members} members"); 

See: Strings

let first\_letter\_of\_alphabet = 'a'; let explicit\_char: char = 'F'; let implicit\_char = '8'; let emoji = "\u{1f600}"; // => 😀 

let true\_val: bool = true; let false\_val: bool = false; let just\_a\_bool = true; let is\_true = 8 < 5; // => false 

let mut sixty\_bit\_float: f64 = 89.90; let thirty\_two\_bit\_float: f32 = 7.90; let just\_a\_float = 69.69; 

let mut a: u32 = 8; let b: u64 = 877; let c: i64 = 8999; let d = -90; 

fn test(){ println!("This is a function!"); } fn main(){ test(); } 

See: Functions

// Line Comments /\*.............Block Comments \*/ /// Outer doc comments //! Inner doc comments 

See: Comment

// Initializing and declaring a variable let some\_variable = "This\_is\_a\_variable"; // Making a variable mutable let mut mutable\_variable = "Mutable"; // Assigning multiple variables let (name, age) = ("ElementalX", 20); // (Global) constant const SCREAMING_SNAKE_CASE:i64 = 9; 

// Prints the output print!("Hello World\n"); // Appends a new line after printing println!("Appending a new line"); // Prints as an error eprint!("This is an error\n"); // Prints as an error with new line eprintln!("This is an error with new line"); 

// Single Placeholder println!("{}", 1); // Multiple Placeholder println!("{} {}", 1, 3); // Positional Arguments println!("{0} is {1} {2}, also {0} is a {3} programming language", "Rust", "cool", "language", "safe"); // Named Arguments println!("{country} is a diverse nation with unity.", country = "India"); // Placeholder traits :b for binary, :0x is for hex and :o is octal println!("Let us print 76 is binary which is {:b} , and hex equivalent is {:0x} and octal equivalent is {:o}", 76, 76, 76); // Debug Trait println!("Print whatever we want to here using debug trait {:?}", (76, 'A', 90)); // New Format Strings in 1.58 let x = "world"; println!("Hello {x}!"); 

fn main() { println!("Hello, World!"); } 

#Compiling and Running

$ rustc Hello\_World.rs $ ./Hello\_World Hello, World!