Arithmetic Operators in Rust: +, -, *, / and %

TL ; DR:

• We can tell computers to perform calculations for us using +, -, *, /:

  println!("{}", 2 + 6); // Prints 8
  println!("{}", 10 - 7); // Prints 3
  println!("{}", 3 * 3); // Prints 9
  println!("{}", 6 / 2); // Prints 3
  

  
  
  

• We can also use variables. In these examples, Rust will replace variable num with its value 6 to do the calculations:

  let num = 6;
  println!("{}", num + 5); // Prints 11
  println!("{}", 10 - num); // Prints 4
  println!("{}", 3 * num); // Prints 18
  println!("{}", num / 2); // Prints 3
  

  
  

Full lesson:

Computers absolutely excel at performing calculations. The "compute" in their name comes from their historical association with providing answers to mathematical questions.

These calculations can be performed either directly with numbers or with variables that are assigned numeric values.

Arithmetic operators are used with numeric values to perform common mathematical operations:

Note that performing arithmetic on variables does not change the variable - you can only update a variable using the = sign.

Let's go through some examples together to better understand how each operator works:

Addition

// Declare 2 integer variables and initialize them:
let a = 2;
let b = 3;

println!("{}", a + b); // Output: 5

println!("{}", a + 10); // Output: 12

Subtraction

// Declare 2 integer variables and initialize them:
let a = 2;
let b = 3;

println!("{}", a - b); // Output: -1

println!("{}", 10 - b); // Output: 7

Multiplication

// Declare 2 integer variables and initialize them:
let a = 2;
let b = 3;

println!("{}", a * 5); // Output: 10

println!("{}", 2 * a * b); // Output: 12

Division

In Rust, division between integers returns only the integral part of the result:

// Declare 2 integer variables and initialize them:
let a = 2;
let b = 3;

println!("{}", 20 / 3); // Output: 6

println!("{}", b / a); // Output: 1

If we want to get the real result of the division, at least one of the terms has to be a floating-point number (f64):

// Declare 2 integer variables and initialize them:
let a = 2;
let b = 3;

println!("{}", 5.0_f64 / 2.0); // Output: 2.5

println!("{}", b as f64 / a as f64); // Output: 1.5

Assignment
Follow the Coding Tutorial and let's practice with arithmetic operators!

Hint
Look at the examples above if you get stuck.