How to Define A Function In Rust?

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In Rust, you can define a function by using the fn keyword followed by the function name, parameters (if any), return type (if any), and the function body enclosed in curly braces. You can define a function at the global scope or within a module.


Here's an example of defining a simple function in Rust:

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fn add(x: i32, y: i32) -> i32 {
    x + y
}

fn main() {
    let result = add(3, 5);
    println!("The result is: {}", result);
}


In the above example, we define a function add that takes two i32 parameters and returns an i32 result. Inside the function body, we simply add the two parameters and return the result.


You can call the function add within the main function or from any other function in your program. Remember that Rust functions are expressions, which means they return a value that can be used in other parts of your code.

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What is pattern matching in Rust functions?

Pattern matching in Rust functions allows you to destructure values and match them against patterns to execute different code branches based on the value. This can be used in match expressions or as function parameters. Pattern matching in Rust functions provides a powerful way to handle different cases or states in your code. It is often used to handle enums, structs, tuples, and other complex data types. By using pattern matching, you can write more expressive and concise code to handle different scenarios in your program.


How to define an anonymous function in Rust?

In Rust, an anonymous function is defined using the |args| body syntax. Here is an example of defining an anonymous function in Rust:

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fn main() {
    let add_one = |x| x + 1;

    println!("{}", add_one(5)); // Output: 6
}


In this example, the add_one variable is assigned to an anonymous function that increments its input by 1. The function takes one argument x and returns x + 1.


How to define a variadic function in Rust?

In Rust, a variadic function can be defined using the ... syntax in the function signature. Here is an example of how to define a variadic function in Rust:

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fn print_numbers(numbers: i32...) {
    for number in numbers {
        println!("{}", number);
    }
}

fn main() {
    print_numbers(1, 2, 3, 4, 5);
}


In this example, the print_numbers function takes a variable number of i32 arguments. The ... syntax in the function signature indicates that the function can take a variable number of arguments. Inside the function, we use a for loop to iterate over the given numbers and print them out.


When calling a variadic function in Rust, you can pass any number of arguments of the specified type. The Rust compiler will handle creating and passing the correct number of arguments to the function.

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