excercises solutions

docs/http/main.go

@@ -0,0 +1,77 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+)
+
+
+type UserResponse struct {
+	Attributes User `json:"attributes"`
+}
+
+// here its used by json := exported
+type User struct {
+	ID         int    `json:"id"`
+	Name       string `json:"name"`
+	AccountIDs []int  `json:"account_ids"`
+}
+// array_of_ints = {array_of_strings}.map(:to_s)
+// convert an array into something else
+// 1. create a second array variable
+// arrayOfInts := make([]int, len(arrayOfStrings))
+// 2. iterate and convert each element
+// for i, v := range arrayOfStrings {
+//   arrayOfInts[i] = ....
+// }
+
+func main() {
+	url := "https://sample-accounts-api.herokuapp.com/users/1"
+	// no underscore in golang
+	resp, err := http.Get(url)
+	// best practice to check and write defer code nearby to original code
+	defer resp.Body.Close() // defer here vs derer after error handling is same in this case
+
+	if err != nil {
+		fmt.Println("error found %v", err) // shadowing error variable... [ from interface error{}] -> avoid naming conflicts with packages
+		return
+	}
+	// return fmt.Errorf("http get %w", err)
+	//error handlling missing
+
+	// defer resp.Body.Close()
+	// defer will be skipped here, but it's ok because an error occurred, so there is no body to close
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		fmt.Println("error found %v", err)
+		return
+	}
+
+	// var result map[string]any
+	// err = json.Unmarshal(body, &result)
+
+	// if err != nil {
+	// 	fmt.Println("error found")
+	// }
+	// const attr = "attributes"
+	// optimization + safety [ type safety ]
+	// attributes, _ := result["attributes"].(map[string]any)
+	// attributesJSON, _ := json.Marshal(attributes)
+	var user UserResponse  // dont use same var name as struct type name
+	err = json.Unmarshal(body, &user)
+
+	if err != nil {
+		fmt.Println("error found")
+	}
+
+	fmt.Println("User: ", user.Attributes.AccountIDs)
+	// fmt.Printf("ID: %d, Account IDs: %v\n", user.ID, user.AccountIDs)
+
+	// user.Attributes.AccountIDs is slice of ints
+	// convert to slice of strings by using strconv.Itoa
+	// use strings.Join() to join the elements with ","
+
+}

docs/http/main_1.go

@@ -0,0 +1,112 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+)
+
+type UserResponse struct {
+	Attributes User `json:"attributes"`
+}
+
+type User struct {
+	ID         int    `json:"id"`
+	Name       string `json:"name"`
+	AccountIDs []int  `json:"account_ids"`
+}
+
+type AccountResponse struct {
+	Attributes Account `json:"attributes"`
+}
+
+type Account struct {
+	ID      int    `json:"id"`
+	UserID  int    `json:"user_id"`
+	Name    string `json:"name"`
+	Balance int    `json:"balance"`
+}
+
+func getUser(userID int) (User, error) {
+	url := fmt.Sprintf("https://sample-accounts-api.herokuapp.com/users/%d", userID)
+	resp, err := http.Get(url)
+	if err != nil {
+		return User{}, err
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return User{}, err
+	}
+
+	var userResponse UserResponse
+	err = json.Unmarshal(body, &userResponse)
+	if err != nil {
+		return User{}, err
+	}
+
+	return userResponse.Attributes, nil
+}
+
+func getAccounts(userID int) ([]Account, error) {
+	url := fmt.Sprintf("https://sample-accounts-api.herokuapp.com/users/%d/accounts", userID)
+	resp, err := http.Get(url)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	var accountResponses []AccountResponse
+	err = json.Unmarshal(body, &accountResponses)
+	if err != nil {
+		return nil, err
+	}
+
+	accounts := make([]Account, len(accountResponses))
+	for i, accountResponse := range accountResponses {
+		accounts[i] = accountResponse.Attributes
+	}
+
+	return accounts, nil
+}
+
+func displayUser(user User, accounts []Account) {
+	fmt.Printf("User: %s\n", user.Name)
+	fmt.Println("Accounts:")
+	totalBalance := 0
+	for _, account := range accounts {
+		fmt.Printf("  - %s: %d\n", account.Name, account.Balance)
+		totalBalance += account.Balance
+	}
+	fmt.Printf("Total Balance: %d\n", totalBalance)
+}
+
+func main() {
+	var userID int
+	_, err := fmt.Scanln(&userID)
+	if err != nil {
+		fmt.Println("Invalid input")
+		return
+	}
+
+	user, err := getUser(userID)
+	if err != nil {
+		fmt.Println("error found")
+		return
+	}
+
+	accounts, err := getAccounts(userID)
+	if err != nil {
+		fmt.Println("error found")
+		return
+	}
+
+	displayUser(user, accounts)
+}

docs/testing/palindrome_test.go

@@ -0,0 +1,33 @@
+package stringutils
+
+import (
+	"testing"
+)
+
+func TestReverse(t *testing.T) {
+	testCases := []struct {
+        name     string
+        input    string
+        expected string
+    }{
+        {"empty string", "", ""},
+        {"single character", "x", "x"},
+        {"palindrome", "aba", "aba"},
+        {"simple string", "qwe", "ewq"},
+        {"with spaces", "qwe rt", "tr ewq"},
+		{"with numbers", "12345", "54321"},
+		{"with special characters", "!@#$%^&*()", ")(*&^%$#@!"},
+		{"with mixed case", "Hello World", "dlroW olleH"},
+		{"with unicode", "こんにちは", "はちにんこ"},
+		{"with emojis", "😀😃😄", "😄😃😀"},
+    }
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			actual := Reverse(tc.input)
+			if actual != tc.expected {
+				t.Errorf("Reverse(%q) = %q; expected %q", tc.input, actual, tc.expected)
+			}
+		})
+	}
+}