Augmented Assignment Operators in Rust in Rust

In programming, it is common to use assignments to modify the contents of a variable.

Remember that everything to the right of the equals sign (=) is evaluated first, so we can say:

my_var = my_var + 5;

to add 5 to my_var.

Since this is such a common pattern, there are operators which do both a mathematical operation and assignment in one step.

One such operator is the += operator:

let mut my_var = 10;
my_var += 5;
println!("{}", my_var); // Output: 15

This code would print 15 to the console. We call my_var += 5 an augmented assignment.

There is one such operator for every other arithmetic operator we've learned:

For subtraction: -=

let mut my_var = 10;
my_var -= 5; // short for my_var = my_var - 5;
println!("{}", my_var); // Output: 5

For multiplication: *=

let mut my_var = 3;
my_var *= 5; // short for my_var = my_var * 5;
println!("{}", my_var); // Output: 15

For division: /=

let mut my_var = 20;
my_var /= 4; // short for my_var = my_var / 4;
println!("{}", my_var); // Output: 5

For remainder: %=

let mut my_var = 11;
my_var %= 3; // short for my_var = my_var % 3;
println!("{}", my_var); // Output: 2

Assignment
Follow the Coding Tutorial and let's do some augmented assignments.

Hint
Look at the examples above if you get stuck.