How to refer a struct member to initialize another member of same struct in default?

help
1

I have below code

struct Rectangle {
    length: i32,
    width: i32,
}

impl Default for Rectangle {
    fn default() -> Self {
        Rectangle {
            length: 10,
            width: length * 2,
        }
    }
}

Here I'm trying to initialize width as 2*length in default. but this is giving me below compilation error.

cannot find value length in this scope

what could be the possible solution here?

2

Can define it as a variable, then use it to define both fields:

impl Default for Rectangle {
    fn default() -> Self {
        let length = 10;
        Rectangle {
            length,
            width: length * 2, // this refers to the variable, not the field
        }
    }
}
1 Like
3

Thanks, this works.

4

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