Else If Statement in Rust

In this tutorial, we will learn about else-if statements in Rust. We will cover the basics of conditional execution using if-else-if statements.

What is an Else-If statement

An else-if statement is a conditional statement that allows multiple conditions to be tested sequentially. It provides a way to execute different code blocks based on different conditions.

Syntax

The syntax for the else-if statement in Rust is:

if condition1 {
    // Code block to execute if condition1 is true
} else if condition2 {
    // Code block to execute if condition2 is true
} else {
    // Code block to execute if none of the conditions are true
}

The else-if statement evaluates the specified conditions in order. The first condition that is true will have its code block executed; if none of the conditions are true, the code block inside the else statement is executed.

Flowchart of Else-If Statement

Example 1: Checking if a Number is Positive, Negative, or Zero

  1. Declare a variable num.
  2. Assign a value to num.
  3. Use an if-else-if statement to check if num is positive, negative, or zero.
  4. Print a message indicating whether num is positive, negative, or zero.

Rust Program

fn main() {
    let num = -5;
    if num > 0 {
        println!("{} is positive.", num);
    } else if num < 0 {
        println!("{} is negative.", num);
    } else {
        println!("{} is zero.", num);
    }
}

Output

-5 is negative.

Example 2: Checking the Grade of a Student

  1. Declare a variable marks.
  2. Assign a value to marks.
  3. Use an if-else-if statement to check the grade based on the marks.
  4. Print a message indicating the grade.

Rust Program

fn main() {
    let marks = 85;
    if marks >= 90 {
        println!("Grade: A");
    } else if marks >= 80 {
        println!("Grade: B");
    } else if marks >= 70 {
        println!("Grade: C");
    } else if marks >= 60 {
        println!("Grade: D");
    } else {
        println!("Grade: F");
    }
}

Output

Grade: B

Example 3: Checking the Temperature Range

  1. Declare a variable temperature.
  2. Assign a value to temperature.
  3. Use an if-else-if statement to check the range of the temperature.
  4. Print a message indicating the temperature range.

Rust Program

fn main() {
    let temperature = 75.5;
    if temperature > 100 {
        println!("It's extremely hot.");
    } else if temperature > 85 {
        println!("It's hot.");
    } else if temperature > 60 {
        println!("It's warm.");
    } else if temperature > 32 {
        println!("It's cold.");
    } else {
        println!("It's freezing.");
    }
}

Output

It's warm.