标签: switch-statement

我是C的新手,我正在尝试使用int数组作为这样的开关的选项号

void totalEntered(float * total, float * inputFigure)
{
    *total = *total + *inputFigure;
}

int main()
{
    float amountEntered = 0.00;
    float tot = 0.00;
    int option_numbers[3] = {1,2,3,4};
    float a_food = 0.00;
    float a_tab = 0.00;
    float a_trav = 0.00;
    float a_bill = 0.00;

    totalEntered(&tot, &amountEntered);



    printf("Please enter option number from below \n1.food\n2.tabacco\n3.travel\n4.bills\n");
    scanf("%i", option_numbers);
    switch(option_numbers)
    {
    case 1:
        printf("Please Enter an amount: ");
        scanf("%f", amountEntered);
        a_food = a_food + amountEntered;
        totalEntered(&tot, &amountEntered);
        printf("You have spent %f on …

#include <stdio.h>
void main ()
{
    int i=0;
    for (i=0; i<21; i++)
    {
        switch(i)
        {
            case 0:
            i+=5;
            case 1:
            i+=2;
            case 5:
            i+=5;
            default:
            i+=4;

            break;
        }
        printf("%d   ",i);
    }
    getchar();
}

现在这个程序的输出是16 21我不明白为什么这个程序在循环限制小于18时给出这个输出它只给出16但是当值大于18时输出是16 21任何帮助

public int alphCheck(char check){
    switch(check){
        case 'a':
            return 1;
            break;
        case 'b':
            return 2;
            break;
        case 'c':
            return 3;
            break;
        case 'd':
            return 4;
            break;
        case 'e':
            return 5;
            break;
        case 'f':
            return 6;
            break;
        case 'g':
            return 7;
            break;
        case 'h':
            return 8;
            break;
        case 'i':
            return 9;
            break;
        case 'j':
            return 10;
            break;
        case 'k':
            return 11;
            break;
        case 'l':
            return 12;
            break;
        case 'm':
            return 13;
            break;
        case 'n':
            return 14;
            break;
        case 'o':
            return 15;
            break; …

使用 Perl v5.10 我试图嵌套given语句 - 即在满足given初始when情况之一时调用语句。例子：

my $value = "test3";
my $subvalue = "subtest2";
my $content .= "\nvalue:";

given($value) {
    when ('test1') { $content .= "test1" }
    when ('test2 ) { $content .= "test2" }
    when ('test3') {
        given($subvalue) {
            when ('subtest1') { $content .= "subtest1" }
            when ('subtest2') { $content .= "subtest2" }
            when ('subtest3') { $content .= "subtest3" }
            when ('subtest4') { $content .= "subtest4" }
        }
    }
}

我收到以下错误：

test3' 后的名称错误，位于 …

我是C++初学者.我的问题是,如果用户不小心输入了一个字母,程序将发送错误消息,它不会循环回来.这是我的代码:

#include <string>
#include <iostream>

using namespace std;

int main()
{
    int q;
    A:
    cout << "[1] Name";
    cout << "\n[2] Address";
    cout << "\nEnter your choice: ";
    cin >> q;

    switch (q)
    {
    case 1:
        cout << "XXXXXXXXXX" << endl;
        break;
    case 2:
        cout << "XXXXXXXXXX" << endl;
        break;
    default:
        cout << "Error! Enter only numbers from 1 - 2" << endl;
        goto A;
    }
    return 0;
}

产出是:

[1] Name
[2] Address
Enter your choice: x
Error! Enter …

如果我有Rust代码:

let x: u8;
let y = match x {
    0 => "0",
    1 => "1",
    // ...
    255 => "255",
    _ => unreachable!(),
};

它会比C代码快(或更快):

byte x;
char* y;
switch(x) {
  case 0: y = "0"; break;
  case 1: y = "1"; break;
  ...
  case 255: y = "255"; break;
}

我想知道Rust是否在程序集中实现了类似跳转表的任何东西.

switch (newButton.fileExtension)
            {
                case ".txt":
                    newButton.Image = System.Drawing.Image.FromFile(@"Some Directory\Project Code\Project images\Text document.png");
                    break;
                case (".png") || (".jpg") || (".gif"):
                    newButton.Image = System.Drawing.Image.FromFile(@"Some Directory\Project images\Picture document.png");
                    break;
                case ".doc":
                    newButton.Image = System.Drawing.Image.FromFile(@"Some Directory\Project Code\Project images\Word Document.png");
                    break;
                default:
                    newButton.Image = System.Drawing.Image.FromFile(@"Some Directory\Project Code\Project images\Unknown Document.png");
                    break;

            }

我想使用switch语句来检查newButton文件类型是什么,但是c#不允许你做"string"|| "字符串"是否有解决方法,或者我应该使用If Else语句？

我是golang的新手,从python切换到golang.如何在"开关"中转换此if if语句

type Client struct {
    Type  string `json:"type"`
} 

然后我像这样初始化这个结构:

a:= Client{"v1"}

if a.Type == "v1" {
    if err := apiClient.v1("I am version one"); err != nil {
        log.Printf(" Error: Sending type v1")
        return err
    }
} else if a.Type == "v2" {
    if err := apiClient.v2("I am version 2"); err != nil {
        log.Printf(" Error: Sending type v2\n")
        return err
    }
}  else {
        return errors.New(fmt.Sprintf(" Error: Invalid mertype...This Type"))
    }

你好，我有一个简单的 switch case 语句，它有一个错误“在预期返回‘字符串’的函数中缺少返回”

我只能看到我正在归还所有东西。没有 if 语句，所以它不能是一个缺失的返回。

enum Sign { case rock, paper, scissors }

func detectWinner(player: Sign, bot: Sign) -> String{
    switch player{
    case .rock:
        switch(bot){
        case .rock: return "You Tied"
        case .paper: return "You Lost"
        case .scissors: return "You Won"
        }
    case .paper:
        switch(bot){
            case .rock: return "You Won"
            case .paper: return "You Tied"
            case .scissors: return "You Lost"
        }
    case .scissors:
        switch(bot){
            case .rock: return "You Lost"
            case .paper: return "You Won"
            case .scissors: return "You Tied" …

符号:C和C++中的含义是什么？为什么它与开关和外壳一起使用？我搜索过网络,我得到的唯一答案是,它是一个标签并与goto语句一起使用.