Rust Print Output

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Index:

• Rust print!

• Rust println!

• How to print a variable

• How to print multiple variables

• Alternative place holder to {}

• Print Newline Character

• Rust Showing a progress bar ⇐ https://rust-cli.github.io/book/tutorial/output.html

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Two Macro:

In Rust, there are two variations of the print:

• print!()
• println!()

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Rust print!

The print! macro prints the text inside double quotes.

fn main() {
    print!("Rust is fun!"); 
    print!("I love Rust programming");
}

Output:

Rust is fun! I love Rust programming.

The printed strings are on the same line

To separate the print strings in different lines, we can use the println! macro which will add a new line character at the end.

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Rust println!

fn main() {
    println!("Rust is fun!");
    println!("I love Rust programming.");
}

Output:

Rust is fun!
I love Rust programming.

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How to print a variable

We can use the same print! and println! macros to print variables in Rust.

fn main() {
    let age = 31;
  
    println!("{}", age);
    print!("{}", age);
}

Output:

31
31

Nota: Here, {} is a placeholder which is replaced by the value of the variable after the comma.

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How to print multiple variables

We can use a single println! or print! macro to print multiple variables together.

fn main() {
    let age = 31;
    let name = "Jack";
  
    println!("Name = {}, Age = {}", name, age);
}

Output:

Age = 31

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Alternative place holder to {}

1) You can also specify the numbering for placeholders to print variables in different order.

fn main() {
    let age = 31;
    let name = "Jack";
  
    println!("Name = {1}, Age = {0}", age, name);
}

Here, the placeholder:

• {0} is replaced by the first variable name
• {1} is replaced by the second variable age

2) you can also use the variable names directly inside the placeholder

fn main() {
    let age = 31;
    let name = "Jack";
  
    // print the variables using println!
    println!("Name = {name}, Age = {age}");
}

Output:

Name = Jack, Age = 31

Instead of using variables separately after comma, we have directly provided them inside the placeholder.

• {name} - prints the value of the name variable
• {age} - prints the value of the age variable

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Print Newline Character

In Rust, we can print newline character(s) using the \n escape sequence. For example,

fn main() {
    print!("Rust is fun!\nI love Rust");
}

Output:

Rust is fun!
I love Rust 

Here, \n is an escape sequence that adds a new line character. Hence, the text after \n is printed in a new line.

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