To start learning a programming language we start by printing hello world message on the screen. Let's do that.
To start :
1 - create a file with extension .rs for example hello.rs and open the file in the code editor
2 - inside file place this code :
fn main(){
println!("Hello world");
}
3 - To compile and run this command in the folder containing the file :
# to compile replace hello.rs by the name of your file
rustc hello.rs
# to run
./hello
4 - You will get "hello world" on the screen.
In rust there is 2 types of programs : binary or executable program and library. We will see library later in this course.
1 - Every binary program start it's execution in a special function called main. Here we have :
fn main(){
}
fn = keyword to tell the compiler that the following is a function
main = the name of the function, it's a special name.
() = parenthesis is transmit data (called arguments) to this function.
{} = this is function body limits, it's use to hold all code that is part of the function.
2 - instruction
Inside the function body we write statement and expressions that the function will execute. Here we have :
println!("Hello world");
println! = is a macro is rust (we will see them later), here this macro is used to print a message "Hello world" on the the screen.
() = is used to transmit arguments or data to the macro.
"hello world" = is the message to print on the screen.
semi-colon (;) = in rust every statement end with semi-colon, to indicate the end of the statement.