first

course/11-pointers/exercises/2-pointers_practice/code.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"fmt"
+)
+
+func removeProfanity(message *string) {
+	// ?
+}
+
+// don't touch below this line
+
+func test(messages []string) {
+	for _, message := range messages {
+		removeProfanity(&message)
+		fmt.Println(message)
+	}
+}
+
+func main() {
+	messages1 := []string{
+		"well shoot, this is awful",
+		"dang robots",
+		"dang them to heck",
+	}
+
+	messages2 := []string{
+		"well shoot",
+		"Allan is going straight to heck",
+		"dang... that's a tough break",
+	}
+
+	test(messages1)
+	test(messages2)
+}

course/11-pointers/exercises/2-pointers_practice/complete.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+)
+
+func removeProfanity(message *string) {
+	messageVal := *message
+	messageVal = strings.ReplaceAll(messageVal, "dang", "****")
+	messageVal = strings.ReplaceAll(messageVal, "shoot", "*****")
+	messageVal = strings.ReplaceAll(messageVal, "heck", "****")
+	*message = messageVal
+}
+
+// don't touch below this line
+
+func test(messages []string) {
+	for _, message := range messages {
+		removeProfanity(&message)
+		fmt.Println(message)
+	}
+}
+
+func main() {
+	messages1 := []string{
+		"well shoot, this is awful",
+		"dang robots",
+		"dang them to heck",
+	}
+
+	messages2 := []string{
+		"well shoot",
+		"Allan is going straight to heck",
+		"dang... that's a tough break",
+	}
+
+	test(messages1)
+	test(messages2)
+}

course/11-pointers/exercises/2-pointers_practice/expected.txt

@@ -0,0 +1,6 @@
+well *****, this is awful
+**** robots
+**** them to ****
+well *****
+Allan is going straight to ****
+****... that's a tough break

course/11-pointers/exercises/2-pointers_practice/readme.md

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+# Pointers
+
+Pointers hold the memory address of a value.
+
+The `*` syntax defines a pointer:
+
+```go
+var p *int
+```
+
+A pointer's zero value is `nil`
+
+The & operator generates a pointer to its operand.
+
+```go
+myString := "hello"
+myStringPtr = &myString
+```
+
+The * dereferences a pointer to gain access to the value
+
+```go
+fmt.Println(*myStringPtr) // read myString through the pointer
+*myStringPtr = "world"    // set myString through the pointer 
+```
+
+Unlike C, Go has no [pointer arithmetic](https://www.tutorialspoint.com/cprogramming/c_pointer_arithmetic.htm)
+
+## Just because you can doesn't mean you should
+
+We're doing this exercise to understand that pointers **can** be used in this way. That said, pointers can be *very* dangerous. It's generally a better idea to have your functions accept non-pointers and return new values rather than mutating pointer inputs.
+
+## Assignment
+
+Complete the `removeProfanity` function.
+
+It should use the [strings.ReplaceAll](https://pkg.go.dev/strings#ReplaceAll) function to replace all instances of the following words in the input `message` with asterisks.
+
+* "dang" -> "****"
+* "shoot" -> "*****"
+* "heck" -> "****"
+
+It should *mutate* the value in the pointer and return nothing.
+
+Do *not* alter the function signature.