algorithm - Go 程序不显示分配给变量的 Sliced Int 的期望结果

coder 2023-07-03 原文

我的程序的 printRecipeOfTheDay 函数有问题。例如，程序随机选择 0 并分配给我创建的星期一变量，当我将“recipe1”传递给函数“printRecipeOfTheDay”时，我没有输出或空值。知道我可能搞砸了什么吗？

        if monday == 0 {
            fmt.Println(0)
            printRecipeOfTheDay(recipe1)
        } else if monday == 1 {
            fmt.Println(1)

整个程序如下:

package main

import (
    "fmt"
    "math/rand"
    "time"
)

//Struct for Recipe below
type Recipe struct { //Struct for recipe information
    name        string
    prepTime    int
    cookTime    int
    Ingredients []string //this is now a slice that will accept multiple elements
    ID          int
    Yield       int
}

//function to print Recipe
func printRecipe(recipe Recipe) {
    fmt.Printf("Recipe Name : %s\n", recipe.name)
    fmt.Printf("Prep Time : %d\n", recipe.prepTime)
    fmt.Printf("Cook Time : %d\n", recipe.cookTime)
    fmt.Printf("Ingredients : %s\n", recipe.Ingredients)
    fmt.Printf("Recipe ID : %d\n", recipe.ID)
}

//Returns total time by addings cookTime and prepTime
func totalTime(recipe Recipe) {
    fmt.Printf("The total time for this recipe is %d\n", recipe.cookTime+recipe.prepTime)
}

func main() {
    var recipe1 Recipe //Declare recipe1 of Type Recipe
    var recipe2 Recipe
    var recipe3 Recipe

    //choose random number for recipe
    r := rand.New(rand.NewSource(time.Now().UnixNano()))
    i := r.Perm(5)
    fmt.Printf("%v\n", i)
    fmt.Printf("%d\n", i[0])

    //assign slices of int from Perm to variables assigned days of the week
    var monday = i[0]
    var tuesday = i[1]
    var wednesday = i[2]
    var thursday = i[3]
    var friday = i[4]

    //testing printing of variables assigned to days
    fmt.Printf("This is for the day Monday %d\n", monday)
    fmt.Printf("%d\n", tuesday)
    fmt.Printf("%d\n", wednesday)
    fmt.Printf("%d\n", thursday)
    fmt.Printf("%d\n", friday)

    //logic for Mondays Recipe
    if monday == 0 {
        fmt.Println(0)
        printRecipeOfTheDay(recipe1)
    } else if monday == 1 {
        fmt.Println(1)
        printRecipeOfTheDay(recipe2)
    } else if monday == 2 {
        fmt.Println(2)
        printRecipeOfTheDay(recipe3)
    } else if monday == 3 {
        fmt.Println(3)
    }
    /* recipe1 specifications */
    recipe1.name = "BBQ Pulled Chicken"
    recipe1.prepTime = 25
    recipe1.cookTime = 5
    recipe1.Ingredients = append(
        recipe1.Ingredients,
        "1 8-ounce can reduced-sodium tomato sauce",
    )
    recipe1.Ingredients = append(
        recipe1.Ingredients,
        "1/2 medium onion (grated),",
    )
    recipe1.ID = 1
    recipe1.Yield = 8

    /* Recipe 2 specifications */

    recipe2.name = "Steak Tacos with Pineapple"
    recipe2.prepTime = 45
    recipe2.cookTime = 45
    recipe2.Ingredients = append(
        recipe2.Ingredients,
        "3 tablespoons soy sauce,",
    )
    recipe2.Ingredients = append(
        recipe2.Ingredients,
        "1 tablespoon finely grated garlic,",
    )
    recipe2.Ingredients = append(
        recipe2.Ingredients,
        "1 tablespoon finely grated peeled fresh ginger,",
    )
    recipe2.Ingredients = append(
        recipe2.Ingredients,
        "1 1/2 pounds skirt steak, cut into 5-inch lengths,",
    )
    recipe2.Ingredients = append(
        recipe2.Ingredients,
        "Salt",
    )
    recipe2.Ingredients = append(
        recipe2.Ingredients,
        "Pepper",
    )
    recipe2.ID = 2
    recipe2.Yield = 4

    recipe3.name = "Simple Lemon Herb Chicken"
    recipe3.prepTime = 10
    recipe3.cookTime = 15
    recipe3.Ingredients = append(
        recipe3.Ingredients,
        "2 skinless boneless chicken breast halves,",
    )
    recipe3.Ingredients = append(
        recipe3.Ingredients,
        "1 Lemon,",
    )
    recipe3.Ingredients = append(
        recipe3.Ingredients,
        "Salt and Pepper to taste,",
    )
    recipe3.Ingredients = append(
        recipe3.Ingredients,
        "1 tablespoon olive oil,",
    )
    recipe3.Ingredients = append(
        recipe3.Ingredients,
        "2 sprigs fresh parsley (for garnish),",
    )
    recipe3.Ingredients = append(
        recipe3.Ingredients,
        "1 pinch dried oregano,",
    )
    recipe3.ID = 3
    recipe3.Yield = 2

    //call to printRecipe function below
    printRecipe(recipe1)
    totalTime(recipe1)
    printRecipe(recipe2)
    totalTime(recipe2)
    printRecipe(recipe3)
    totalTime(recipe3)
}

//function to print the winner for recipe of the day to use
//for either lunch or dinner
func printRecipeOfTheDay(recipe Recipe) {
    fmt.Printf("The recipe of the day is : %s\n", recipe.name)
}

最佳答案

您的陈述顺序错误。当您尝试打印食谱时，您已经声明了它，但您没有进行任何初始化，因此它应该为 null。

package main

import (
    "fmt"
    "math/rand"
    "time"
)

//Struct for Recipe below
type Recipe struct { //Struct for recipe information
    name        string
    prepTime    int
    cookTime    int
    Ingredients []string //this is now a slice that will accept multiple elements
    ID          int
    Yield       int
}

//function to print Recipe
func printRecipe(recipe Recipe) {
    fmt.Printf("Recipe Name : %s\n", recipe.name)
    fmt.Printf("Prep Time : %d\n", recipe.prepTime)
    fmt.Printf("Cook Time : %d\n", recipe.cookTime)
    fmt.Printf("Ingredients : %s\n", recipe.Ingredients)
    fmt.Printf("Recipe ID : %d\n", recipe.ID)
}

//Returns total time by addings cookTime and prepTime
func totalTime(recipe Recipe) {
    fmt.Printf("The total time for this recipe is %d\n", recipe.cookTime+recipe.prepTime)
}

func main() {
    var recipe1 Recipe //Declare recipe1 of Type Recipe
    var recipe2 Recipe
    var recipe3 Recipe


        /* recipe1 specifications */
    recipe1.name = "BBQ Pulled Chicken"
    recipe1.prepTime = 25
    recipe1.cookTime = 5
    recipe1.Ingredients = append(
        recipe1.Ingredients,
        "1 8-ounce can reduced-sodium tomato sauce",
    )
    recipe1.Ingredients = append(
        recipe1.Ingredients,
        "1/2 medium onion (grated),",
    )
    recipe1.ID = 1
    recipe1.Yield = 8

    /* Recipe 2 specifications */

    recipe2.name = "Steak Tacos with Pineapple"
    recipe2.prepTime = 45
    recipe2.cookTime = 45
    recipe2.Ingredients = append(
        recipe2.Ingredients,
        "3 tablespoons soy sauce,",
    )
    recipe2.Ingredients = append(
        recipe2.Ingredients,
        "1 tablespoon finely grated garlic,",
    )
    recipe2.Ingredients = append(
        recipe2.Ingredients,
        "1 tablespoon finely grated peeled fresh ginger,",
    )
    recipe2.Ingredients = append(
        recipe2.Ingredients,
        "1 1/2 pounds skirt steak, cut into 5-inch lengths,",
    )
    recipe2.Ingredients = append(
        recipe2.Ingredients,
        "Salt",
    )
    recipe2.Ingredients = append(
        recipe2.Ingredients,
        "Pepper",
    )
    recipe2.ID = 2
    recipe2.Yield = 4

    recipe3.name = "Simple Lemon Herb Chicken"
    recipe3.prepTime = 10
    recipe3.cookTime = 15
    recipe3.Ingredients = append(
        recipe3.Ingredients,
        "2 skinless boneless chicken breast halves,",
    )
    recipe3.Ingredients = append(
        recipe3.Ingredients,
        "1 Lemon,",
    )
    recipe3.Ingredients = append(
        recipe3.Ingredients,
        "Salt and Pepper to taste,",
    )
    recipe3.Ingredients = append(
        recipe3.Ingredients,
        "1 tablespoon olive oil,",
    )
    recipe3.Ingredients = append(
        recipe3.Ingredients,
        "2 sprigs fresh parsley (for garnish),",
    )
    recipe3.Ingredients = append(
        recipe3.Ingredients,
        "1 pinch dried oregano,",
    )
    recipe3.ID = 3
    recipe3.Yield = 2

    //choose random number for recipe
    r := rand.New(rand.NewSource(time.Now().UnixNano()))
    i := r.Perm(5)
    fmt.Printf("%v\n", i)
    fmt.Printf("%d\n", i[0])

    //assign slices of int from Perm to variables assigned days of the week
    var monday = i[0]
    var tuesday = i[1]
    var wednesday = i[2]
    var thursday = i[3]
    var friday = i[4]

    //testing printing of variables assigned to days
    fmt.Printf("This is for the day Monday %d\n", monday)
    fmt.Printf("%d\n", tuesday)
    fmt.Printf("%d\n", wednesday)
    fmt.Printf("%d\n", thursday)
    fmt.Printf("%d\n", friday)

    //logic for Mondays Recipe
    if monday == 0 {
        fmt.Println(0)
        printRecipeOfTheDay(recipe1)
    } else if monday == 1 {
        fmt.Println(1)
        printRecipeOfTheDay(recipe2)
    } else if monday == 2 {
        fmt.Println(2)
        printRecipeOfTheDay(recipe3)
    } else if monday == 3 {
        fmt.Println(3)
    }

    //call to printRecipe function below
    printRecipe(recipe1)
    totalTime(recipe1)
    printRecipe(recipe2)
    totalTime(recipe2)
    printRecipe(recipe3)
    totalTime(recipe3)
}

//function to print the winner for recipe of the day to use
//for either lunch or dinner
func printRecipeOfTheDay(recipe Recipe) {
    fmt.Printf("The recipe of the day is : %s\n", recipe.name)
}

我刚刚在那里快速剪切和粘贴，因为我现在很忙。稍后我可能会对其进行编辑，这只是为了风格和可读性。我建议制作一个 initRecipes 方法并让它返回一个 []Recipe 并使用复合文字语法进行初始化而不是一遍又一遍地调用 append。

关于algorithm - Go 程序不显示分配给变量的 Sliced Int 的期望结果，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/35328272/

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