Boolean link

The boolean variable can take a value either true or false.

Example link

The following code explains how to define a boolean variable in three different ways:

• Explicit Definition

The following code explicitly defines the variable using the bool keyword:

  fn main() {
    //explicitly define a bool
    let is_bool:bool = true;
    println!("explicitly_defined: {}", is_bool);
}
  

Output

  explicitly_defined: true
  

Implicit Definition link

The following code implicitly defines the boolean type of a variable by assigning the value true or false to the variable.

  fn main() {
    // assign a boolean value
    let a = true;
    let b = false;
    println!("a: {}", a);
    println!("b: {}", b);
}
  

Result of an Expression link

The result of an expression that evaluates to either true or false (for example a comparison of two values) can be assigned to an implicit boolean variable

  fn main() {
    // get a value from an expression
    let c = 10 > 2;
    println!("c: {}", c);
}
  

Output

  c: true
  

Quiz link

Test your understanding of boolean data type in Rust!