diff --git a/examples/issue-loop-struct-slice/issue-loop-struct-slice.go b/examples/issue-loop-struct-slice/issue-loop-struct-slice.go index f8026e8..ffdb01d 100644 --- a/examples/issue-loop-struct-slice/issue-loop-struct-slice.go +++ b/examples/issue-loop-struct-slice/issue-loop-struct-slice.go @@ -1,8 +1,14 @@ -// interview questions: +// Challenge: // // What is expected output? // // How to fix this code? +// +// Reference: [Go Wiki: Range Clauses](https://go.dev/wiki/Range) +// +// Reference: [Should you use slices of pointers to structs?](https://www.willem.dev/articles/slice-of-pointers-structs/) +// +// Reference: [Go Spec: For statements](https://go.dev/ref/spec#For_statements) package main @@ -26,19 +32,23 @@ func main() { fmt.Printf("player %s has score %d\n", p.name, p.score) } - // (End of Question) + // (End of Challenge) // ---------- // Explaination: - // The player struct is stored in the backing array of the slice players // - // `p` is actually only a copy of the original player + // - The player struct is stored in the backing array of the slice players + // + // - p is declaredin in range clause using a form of [short variable declaration (:=)](https://go.dev/ref/spec#Short_variable_declarations). The variables have the types of their respective iteration values. + // + // - `p` is only a copy of the original player + // + // - when updating `p.score`, it only updates the "copy" of the player in the slice for _, p := range players { p.score += 10 } // How to fix it? - fmt.Println("---- After fix ------") // Directly access the player in the slice for i := range players { @@ -48,12 +58,4 @@ func main() { for _, p := range players { fmt.Printf("player %s has score %d\n", p.name, p.score) } - - // Output: - // - // player Bob has score 20 - // - // player Alice has score 217 } - -// Reference: [Should you use slices of pointers to structs?](https://www.willem.dev/articles/slice-of-pointers-structs/) diff --git a/examples/issue-loop-struct-slice/issue-loop-struct-slice.hash b/examples/issue-loop-struct-slice/issue-loop-struct-slice.hash index 4cbf37c..646f5a4 100644 --- a/examples/issue-loop-struct-slice/issue-loop-struct-slice.hash +++ b/examples/issue-loop-struct-slice/issue-loop-struct-slice.hash @@ -1,2 +1,2 @@ -1acf36d67df9c219102a45e722d1cbb38dbd8ce5 -b5YAS_z1uop +7d7891806eda3e24148d21ce6a31e2fbaf3ea623 +gb9N6mi5JjT diff --git a/public/issue-loop-struct-slice b/public/issue-loop-struct-slice index 0d43f6a..4b313ca 100644 --- a/public/issue-loop-struct-slice +++ b/public/issue-loop-struct-slice @@ -27,12 +27,18 @@ -

interview questions:

+

Challenge:

What is expected output?

How to fix this code?

+

Reference: Go Wiki: Range Clauses

+ +

Reference: Should you use slices of pointers to structs?

+ +

Reference: Go Spec: For statements

+ @@ -45,7 +51,7 @@ - + 
package main
@@ -109,7 +115,7 @@ -

(End of Question)

+

(End of Challenge)

@@ -122,10 +128,17 @@ -

Explaination: -The player struct is stored in the backing array of the slice players

+

Explaination:

+ + @@ -142,32 +155,24 @@ The player struct is stored in the backing array of the slice players

How to fix it?

- - - - - - - - - -

Directly access the player in the slice

- - 
    fmt.Println("---- After fix ------")
+          
+    fmt.Println("---- After fix ------")
 

           
         
         
         
           
-            
+            
Directly access the player in the slice

+
           
           
             
-          
    for i := range players {
+          
+    for i := range players {
         players[i].score += 10
     }
 

@@ -178,43 +183,16 @@ The player struct is stored in the backing array of the slice players

           
             
           
-          
+          
             
           
    for _, p := range players {
         fmt.Printf("player %s has score %d\n", p.name, p.score)
     }
-

-          
-        
-        
-        
-          
-            
Output:

-
-
player Bob has score 20

-
-
player Alice has score 217

-
-          
-          
-            
-          
 }
 

           
         
         
-        
-          
-            
Reference: Should you use slices of pointers to structs?

-
-          
-          
-            
-          
-          
-        
-        
       
       
       
@@ -250,7 +228,7 @@ The player struct is stored in the backing array of the slice players

diff --git a/public/issue-loop-struct-slice.html b/public/issue-loop-struct-slice.html
index 0d43f6a..4b313ca 100644
--- a/public/issue-loop-struct-slice.html
+++ b/public/issue-loop-struct-slice.html
@@ -27,12 +27,18 @@ 
Go by Example: Issue: Loop Struct Slice

@@ -109,7 +115,7 @@ 
Go by Example: Issue: Loop Struct Slice

-          
-        
-        
-        
-          
-          
-        
-        
-        
-          
-          
         
-        
-          
-          
-        
-        
       

     
     
     
   
         
         

           
-            
interview questions:

+            
Challenge:

 
 
What is expected output?

 
 
How to fix this code?

 
+
Reference: Go Wiki: Range Clauses

+
+
Reference: Should you use slices of pointers to structs?

+
+
Reference: Go Spec: For statements

+
           		
           
             
@@ -45,7 +51,7 @@ 
Go by Example: Issue: Loop Struct Slice

             
           		
           
-            
+            
           
package main
 

           		
         
         

           
-            
(End of Question)

+            
(End of Challenge)

 
 

 
@@ -122,10 +128,17 @@ 
Go by Example: Issue: Loop Struct Slice

         
         

           
-            
Explaination:
-The player struct is stored in the backing array of the slice players

+            
Explaination:

+
+
    
+
  • The player struct is stored in the backing array of the slice players
    • 
+
+
  • p is declaredin in range clause using a form of short variable declaration (:=). The variables have the types of their respective iteration values.
    • 
+
+
  • p is only a copy of the original player
    • 
 
-
    p is actually only a copy of the original player
    
+
  • when updating p.score, it only updates the “copy” of the player in the slice
    • 
+

 
           		
           
@@ -142,32 +155,24 @@ 
Go by Example: Issue: Loop Struct Slice

           		
             
How to fix it?

 
-          		
-            
-          
-          

-            
Directly access the player in the slice

-
           		
           
             
-          
    fmt.Println("---- After fix ------")
+          
+    fmt.Println("---- After fix ------")
 

           

         

         
         

           
-            
+            
Directly access the player in the slice

+
           		
           
             
-          
    for i := range players {
+          
+    for i := range players {
         players[i].score += 10
     }
 

@@ -178,43 +183,16 @@ 
Go by Example: Issue: Loop Struct Slice

           

             
           
+          
             
           
    for _, p := range players {
         fmt.Printf("player %s has score %d\n", p.name, p.score)
     }
-

-          

-            
Output:

-
-
player Bob has score 20

-
-
player Alice has score 217

-
-          		
-            
-          
 }
 

           		
         

-            
Reference: Should you use slices of pointers to structs?

-
-          		
-            
-          
-          

       
       
@@ -250,7 +228,7 @@ 
Go by Example: Issue: Loop Struct Slice