2020-12-25 14:16:02 +00:00
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< ol class = "chapter" > < li class = "chapter-item expanded " > < a href = "Chapter_0.html" > < strong aria-hidden = "true" > 1.< / strong > Update< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_1.html" > < strong aria-hidden = "true" > 2.< / strong > Introduction< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_2.html" > < strong aria-hidden = "true" > 3.< / strong > Who am I?< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_3.html" > < strong aria-hidden = "true" > 4.< / strong > Writing Rust in Easy English< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_4.html" > < strong aria-hidden = "true" > 5.< / strong > Rust Playground< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_5.html" > < strong aria-hidden = "true" > 6.< / strong > 🚧 and ⚠️< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_6.html" class = "active" > < strong aria-hidden = "true" > 7.< / strong > Comments< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_7.html" > < strong aria-hidden = "true" > 8.< / strong > Types< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_8.html" > < strong aria-hidden = "true" > 9.< / strong > Type inference< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_9.html" > < strong aria-hidden = "true" > 10.< / strong > Printing 'hello, world!'< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_10.html" > < strong aria-hidden = "true" > 11.< / strong > Display and debug< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_11.html" > < strong aria-hidden = "true" > 12.< / strong > Mutability (changing)< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_12.html" > < strong aria-hidden = "true" > 13.< / strong > The stack, the heap, and pointers< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_13.html" > < strong aria-hidden = "true" > 14.< / strong > More about printing< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_14.html" > < strong aria-hidden = "true" > 15.< / strong > Strings< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_15.html" > < strong aria-hidden = "true" > 16.< / strong > const and static< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_16.html" > < strong aria-hidden = "true" > 17.< / strong > More on references< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_17.html" > < strong aria-hidden = "true" > 18.< / strong > Mutable references< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_18.html" > < strong aria-hidden = "true" > 19.< / strong > Giving references to functions< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_19.html" > < strong aria-hidden = "true" > 20.< / strong > Copy types< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_20.html" > < strong aria-hidden = "true" > 21.< / strong > Collection types< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_21.html" > < strong aria-hidden = "true" > 22.< / strong > Vectors< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_22.html" > < strong aria-hidden = "true" > 23.< / strong > Tuples< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_23.html" > < strong aria-hidden = "true" > 24.< / strong > Control flow< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_24.html" > < strong aria-hidden = "true" > 25.< / strong > Structs< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_25.html" > < strong aria-hidden = "true" > 26.< / strong > Enums< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_26.html" > < strong aria-hidden = "true" > 27.< / strong > Loops< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_27.html" > < strong aria-hidden = "true" > 28.< / strong > Implementing structs and enums< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_28.html" > < strong aria-hidden = "true" > 29.< / strong > Destructuring< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_29.html" > < strong aria-hidden = "true" > 30.< / strong > References and the dot operator< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_30.html" > < strong aria-hidden = "true" > 31.< / strong > Generics< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_31.html" > < strong aria-hidden = "true" > 32.< / strong > Option and Result< / a > < / li > < li class = "chapter-item expanded " > < a href = "Chapter_32.html" >
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< h2 > < a class = "header" href = "#comments" id = "comments" > Comments< / a > < / h2 >
2021-02-01 08:14:31 +00:00
< p > < a href = "https://youtu.be/fJ7jBZG_Rpo" > See this chapter on YouTube< / a > < / p >
2020-12-25 14:16:02 +00:00
< p > Comments are made for programmers to read, not the computer. It's good to write comments to help other people understand your code. It's also good to help you understand your code later. (Many people write good code but then forget why they wrote it.) To write comments in Rust you usually use < code > //< / code > :< / p >
< pre > < pre class = "playground" > < code class = "language-rust" > fn main() {
// Rust programs start with fn main()
// You put the code inside a block. It starts with { and ends with }
let some_number = 100; // We can write as much as we want here and the compiler won't look at it
}
< / code > < / pre > < / pre >
< p > When you do this, the compiler won't look at anything to the right of the < code > //< / code > .< / p >
< p > There is another kind of comment that you write with < code > /*< / code > to start and < code > */< / code > to end. This one is useful to write in the middle of your code.< / p >
< pre > < pre class = "playground" > < code class = "language-rust" > fn main() {
let some_number/*: i16*/ = 100;
}
< / code > < / pre > < / pre >
< p > To the compiler, < code > let some_number/*: i16*/ = 100;< / code > looks like < code > let some_number = 100;< / code > .< / p >
< p > The < code > /* */< / code > form is also useful for very long comments over more than one line. In this example you can see that you need to write < code > //< / code > for every line. But if you type < code > /*< / code > , it won't stop until you finish it with < code > */< / code > .< / p >
< pre > < pre class = "playground" > < code class = "language-rust" > fn main() {
let some_number = 100; /* Let me tell you
a little about this number.
It's 100, which is my favourite number.
It's called some_number but actually I think that... */
let some_number = 100; // Let me tell you
// a little about this number.
// It's 100, which is my favourite number.
// It's called some_number but actually I think that...
}
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