Hello i would like to have a struct initialized with new or default, but somehow i do it wrong, i am now searching the web for hours but could not find anything that helped My Example Code: struct MyStruct { a: Option<String>, b: Option<String>, c: Option<String>, d: Option<i32>, …

struct MyStruct { a: Option<String>, b: Option<String>, c: Option<String>, d: Option<i32>, e: Option<String>, } impl MyStruct { fn new(a: String, b: String, c: String, d: i32, e: String) -> MyStruct { MyStruct { a: Some(a), b: Some(b), c: Some(c),…

For more about Option enum this link has some more bits about Option at the bottom more about enum even more about enum Summary of links enum in Rust provide a way to talk about multiple different types while using the one type. enum Choice { Foo(String), Bar(i32) } fn main() { …

Hello KrishnaSannasi i already tried this and get the following error: error: expected one of `!`, `->`, `::`, `;`, or `}`, found `,` --> src/main.rs:24:15 | 24 | a: Some(a), | ^ expected one of `!`, `->`, `::`, `;`, or `}` here error: expected type, found `"a"` --> sr…

Ahhh, sorry. My bad for not testing the code before posting. Fixed it. The problem is that you need to wrap the fields in MyStruct { /* fields here */ } to initialize MyStruct.

how to wrap, can you post the code? Im really a beginner, i tried rust 0.5 Years ago, then it frustrated me and i did something else. And now this is just my second try.

What I mean is MyStruct { a: Some("Hi"), b: None, c: Some("Another Field"), // .. for the rest of the fields } Will initialize the struct MyStruct with the given fields, and you must provide all of the fields.

[image] braindef: Im really a beginner, i tried rust 0.5 Years ago, then it frustrated me and i did something else. And now this is just my second try. That's how I started!

that makes it even more worse Compiling hello_world v0.1.0 error: expected type, found `"Hi"` --> src/main.rs:15:13 | 15 | a: Some("Hi"), struct MyStruct { a: Some("Hi"), b: None, c: Some("Another Field"), d: Some(0), e: Some("TEST"), } in this case the complier …

That is because you are trying to define a struct MyStruct with values as types. I was talking about initializing the MyStruct that you gave a definition for at the beginning. Your definition at the top was correct. struct MyStruct { a: Option<String>, b: Option<String>, c: Option<Str…

Rust does it this way because we don't have special constructor functions like in Java or C++, so to initialize a variable you specify all of the values that the fields should have up front.

How to use Option in Struct (default / new)

OptimisticPeach January 30, 2019, 7:20pm 19

This post by @steveklabnik is points to some good resources.
Actually just checked and the copy resource he points to seems to be out of data, so instead look at this

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How to use Option in Struct (default / new)

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