40 lines
954 B
Markdown
40 lines
954 B
Markdown
# println! and format!
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Printing is handled by a series of [`macros`][macros] defined in [`std::fmt`][fmt]
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some of which include:
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* `format!`: write formatted text to [`String`][string]
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* `print!`: same as `format!` but the text is printed to the console (io::stdout).
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* `println!`: same as `print!` but a newline is appended.
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* `eprint!`: same as `format!` but the text is printed to the standard error (io::stderr).
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* `eprintln!`: same as `eprint!`but a newline is appended.
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All parse text in the same fashion. As a plus, Rust checks formatting
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correctness at compile time.
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## `format!`
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1.🌟
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```rust,editable
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fn main() {
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let s1 = "hello";
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/* Fill in the blank */
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let s = format!(__);
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assert_eq!(s, "hello, world!");
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}
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```
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## `print!`, `println!`
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2.🌟
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```rust,editable
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fn main() {
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/* Fill in the blanks to make it print:
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Hello world, I am
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Sunface!
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*/
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__("hello world, ");
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__("I am");
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__("Sunface!");
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}
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```
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