Rustで途中結果を表示してくれるデバッグ用マクロ(dbg!)
#Rust_マクロ
#Rust
以下は公式
std::dbg - Rust
にある例。
code:rs
fn factorial(n: u32) -> u32 {
if dbg!(n <= 1) {
dbg!(1)
} else {
dbg!(n * factorial(n - 1))
}
}
dbg!(factorial(4));
code:出力
src/main.rs:4
n <= 1 = false
src/main.rs:4
n <= 1 = false
src/main.rs:4
n <= 1 = false
src/main.rs:4
n <= 1 = true
src/main.rs:5
1 = 1
src/main.rs:7
n * factorial(n - 1) = 2
src/main.rs:7
n * factorial(n - 1) = 6
src/main.rs:7
n * factorial(n - 1) = 24
src/main.rs:11
factorial(4) = 24
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