ch03 一般的なプログラミングの概念の和訳を最新版に更新

rust-lang/book@19c40bf

Author: shinmili

listings/ch03-common-programming-concepts/listing-03-02/src/main.rs

@@ -2,6 +2,6 @@ fn main() {
     let condition = true;
     let number = if condition { 5 } else { 6 };
 
-    // numberの値は、{}です
-    println!("The value of number is: {}", number);
+    // numberの値は、{number}です
+    println!("The value of number is: {number}");
 }

listings/ch03-common-programming-concepts/listing-03-03/src/main.rs

@@ -2,7 +2,7 @@ fn main() {
     let mut number = 3;
 
     while number != 0 {
-        println!("{}!", number);
+        println!("{number}!");
 
         number -= 1;
     }

listings/ch03-common-programming-concepts/listing-03-05/src/main.rs

@@ -2,6 +2,6 @@ fn main() {
     let a = [10, 20, 30, 40, 50];
 
     for element in a {
-        println!("the value is: {}", element);
+        println!("the value is: {element}");
     }
 }

listings/ch03-common-programming-concepts/no-listing-01-variables-are-immutable/output.txt

@@ -10,9 +10,9 @@ error[E0384]: cannot assign twice to immutable variable `x`
   |         first assignment to `x`
   |         (`x`への最初の代入)
   |         help: consider making this binding mutable: `mut x`
-3 |     println!("The value of x is: {}", x);
+3 |     println!("The value of x is: {x}");
 4 |     x = 6;
   |     ^^^^^ cannot assign twice to immutable variable
 
 For more information about this error, try `rustc --explain E0384`.
-error: could not compile `variables` due to previous error
+error: could not compile `variables` (bin "variables") due to 1 previous error

listings/ch03-common-programming-concepts/no-listing-01-variables-are-immutable/src/main.rs

@@ -1,6 +1,6 @@
 fn main() {
     let x = 5;
-    println!("The value of x is: {}", x);     // xの値は{}です
+    println!("The value of x is: {x}");     // xの値は{x}です
     x = 6;
-    println!("The value of x is: {}", x);
+    println!("The value of x is: {x}");
 }

listings/ch03-common-programming-concepts/no-listing-02-adding-mut/src/main.rs

@@ -1,6 +1,6 @@
 fn main() {
     let mut x = 5;
-    println!("The value of x is: {}", x);
+    println!("The value of x is: {x}");
     x = 6;
-    println!("The value of x is: {}", x);
+    println!("The value of x is: {x}");
 }

listings/ch03-common-programming-concepts/no-listing-03-shadowing/src/main.rs

@@ -5,8 +5,8 @@ fn main() {
 
     {
         let x = x * 2;
-        println!("The value of x in the inner scope is: {}", x);
+        println!("The value of x in the inner scope is: {x}");
     }
 
-    println!("The value of x is: {}", x);
+    println!("The value of x is: {x}");
 }

listings/ch03-common-programming-concepts/no-listing-05-mut-cant-change-types/output.txt

@@ -8,6 +8,12 @@ error[E0308]: mismatched types          (型が合いません)
 3 |     spaces = spaces.len();
   |              ^^^^^^^^^^^^ expected `&str`, found `usize`
   |                           (&str型を予期しましたが、usizeが見つかりました)
+  |
+help: try removing the method call
+  |
+3 -     spaces = spaces.len();
+3 +     spaces = spaces;
+  |
 
 For more information about this error, try `rustc --explain E0308`.
-error: could not compile `variables` due to previous error
+error: could not compile `variables` (bin "variables") due to 1 previous error

listings/ch03-common-programming-concepts/no-listing-07-numeric-operations/src/main.rs

@@ -14,8 +14,8 @@ fn main() {
     // division
     // 割り算
     let quotient = 56.7 / 32.2;
-    let floored = 2 / 3; // Results in 0
-                         // 結果は0
+    let truncated = -5 / 3; // Results in -1
+                            // 結果は-1
 
     // remainder
     // 余り

listings/ch03-common-programming-concepts/no-listing-09-char/src/main.rs

@@ -1,5 +1,6 @@
 fn main() {
     let c = 'z';
-    let z = 'ℤ';
+    let z: char = 'ℤ'; // with explicit type annotation
+                       // 明示的型注釈付きで
     let heart_eyed_cat = '😻';    //ハート目の猫
 }