标签: switch-statement

我写了一个作业,试着计算一个字符串中每种元音的数字.

它编译得很好,但似乎在循环语句中循环,我看不出我做错了什么,尽管大约一个小时的谷歌搜索.

请帮忙!=]

 import java.util.Scanner;

 public class assignment3b
 {
public static void main(String[] args)
{
    int alpha=0, epsilon=0, india=0, oscar=0, uniform=0, position=0, length;

    String input;

    char letter;

    Scanner scan = new Scanner(System.in);

    System.out.println("Welcome to the vowel parse-o-matic");
    System.out.println("\nThis program will count all lower case vowels in whatever you type.");
    System.out.print("\nPlease enter the word you'd like to have parsed : ");

        input = scan.next();

        System.out.println("\n\nThe word " + input + " has: "); // reprints the word before stripping spaces

        input …

我的Java教科书问我有关以下错误的信息:

switch (score)
        {
            case (score > 90):
                grade = 'A';
                break;
            case (score > 80):
                grade = 'B';
                break;
            default:
                grade = 'C';
        }

我已经知道错误在哪里:

• Switch语句不是为比较而构建的(score > 90); 那是if/else语句.

但是,这让我疑惑:怎么可能一个switch语句有效地占到整数的范围是多少？

我能想到的最明显的例子如下,但我发现它相当蛮力:

switch (score)
    {
        case 90: case 91: case 92: case 94: case 95:
        case 96: case 97: case 98: case 99: case 100:
            grade = 'A';
            break;
        case 80: case 81: case 82: case 84: case 85:
        case 86: case 87: case 88: case …

由于类型不匹配错误(int vs bool),以下程序无法编译

package main

import "fmt"

func main() {
    i := 5
    switch i {
    case 4:
        fmt.Println("4")
    case i > 8:
        fmt.Println("i is greator than 8")
    }
}

作为动态打字背景的人,上面的内容有点文化震撼.所以想知道GO中的这种惯用方式是什么？

这是我的计划,我根据投入的日期找到了一年中的日期.我还必须考虑闰年.我已经完成了所有这些,但当输入一年如12/31/1993时,我得到366这一天是不正确的,因为它不是闰年所以一年中的那一天应该是365.我已经测试过这是否是我的if声明,只是让程序只能测试闰年,并且如果它是一个非闰年就关闭.当输入相同的日期时,程序关闭,告诉我问题不在于我的if语句,而在于我的情况和开关.我不确定发生了什么,或者为什么在日期增加额外的一天.

#include <stdio.h>

int main(void){

    int month,day,year,day_number=0;

    printf("Enter a date in the form (01/02/1996): ");
    scanf("%d/%d/%d", &month,&day,&year);


    if(((year%4 == 0) && (year%100 !=0)) || (year%400==0)){
        goto two;
    }
    else{
        month=month;
        goto one;
    }

    one:
        switch(month)
        {
            case 1:day_number=day;
                break;
            case 2:day_number=31+day; //January+Febuary
                break;
            case 3:day_number=59+day; //January+Febuary+March
                break;
            case 4:day_number=90+day; //January+Febuary+March+April
                break;
            case 5:day_number=120+day; //January+Febuary+March+April+May
                break;
            case 6:day_number=151+day; //January+Febuary+March+April+May+June
                break;
            case 7:day_number=181+day; //January+Febuary+March+April+May+June+July
                break;
            case 8:day_number=212+day; //January+Febuary+March+April+May+June+July+August
                break;
            case 9:day_number=243+day; //January+Febuary+March+April+May+June+July+August+September
                break;
            case 10:day_number=273+day; //January+Febuary+March+April+May+June+July+August+September+October
                break;
            case 11:day_number=304+day; //January+Febuary+March+April+May+June+July+August+September+October+November
                break;
            case …

我有一个测试我正在写一个字符串读取然后获取该字符串并将其应用于switch语句.然后我将字符串与case匹配并设置一个整数值,我将其传递回spec页面,然后将int值传递给我用于if语句的另一个测试.我无法让int传递,所以if语句将无法正常工作.

切换对象:

var appsNotPurchased = 0;
this.checksHomeSublevel = function(mmCode) {
    browser.get('https://iplan-qa.meetingmatrix.com/Home/Index/' + mmCode);
    marketingObjects.level.getText().then(function(text) {
      var homeText = text;
      browser.get('https://iplan-qa.meetingmatrix.com/Home/Apps/' + mmCode);
      expect($('div.apps-subscription > span').getText()).toEqual('iPlan Level: ' + homeText);
      switch (homeText) {
        case 'Select':
          console.log(homeText);
          appsNotPurchased = 6;
          return appsNotPurchased;
          break;
        case 'Content':
          console.log(homeText);
          appsNotPurchased = 0 || 1 || 2 || 3 || 4 || 5 || 6;
          return appsNotPurchased;
          break;
      }


    });

testSpec描述函数:

describe('should upload media: ', function() {

  it('should select add media', function() {
    var mmCode = …

所以我试图制作这个简单的程序,但是当我运行程序时使用switch语句,无论我输入什么,我总是得到默认答案.我如何才能选择正确的声明来表示我输入的数字？

int number;

Console.WriteLine("Enter a number between 0 and 50: ");
number = int.Parse(Console.ReadLine());

switch (number )
{
     case 1:
        Console.WriteLine("Do you not know how to count? That's more than 50!");
        break;
     case 2:
         Console.WriteLine("Did I say you could choose a number below 0?");                 
         break;
     default:
         Console.WriteLine("Good job smarty pants!");
         break;
}        
Console.ReadLine();

以下是用于在playground中执行Switch语句的代码.我执行了几个switch语句而没有使用default.我怀疑的是为什么它对某些人来说是可选的而且对于其他陈述是强制性的.谢谢提前!

let someNumber = 3.5

switch someNumber {

case 2 , 3 , 5 , 7 , 11 , 13 :
  print("Prime numbers")
case 4 , 6 , 24 , 12 , 66 :
  print("Normal numbers")

 }

计数器语句在不使用默认值的情

  let yetAnotherPoint = (3,1)

  switch yetAnotherPoint {

  case let (x,y) where x == y :
   print("(\(x),\(y)) is on the line x == y")
  case let (x,y) where x == -y :
   print("(\(x),\(y)) is on the line x == -y")
  case let (x,y): …

我在Swift 3.0中尝试切换语句使用我的代码,无论我的变量是什么,我都得到A. 为什么我只得到A？

var grade = 45

switch grade {

    case (grade ..< 100):
        print("A")
    case (grade ..< 90):
        print("B")
    case (grade ..< 80):
        print("C")
    case (grade ..< 70):
        print("D")

    default:
        print("F. You failed")
}

#include <iostream>
#include <string>

using namespace std;
int main()
{
    char option='0';
    do
    {

        cin >> option;
        switch (option) 
        {
            case '1':
                cout << "testing 1\n";
                break;
            case '2':
                cout << "testing 2\n";
                break;
            case '3':
                cout << "Thank you, Have a nice day.\n";
                break;

            default:
                cout << "Invalid option, Please enter option (1-3).";
        }

    }while (option != 3);

    return 0;
}

我不知道为什么while循环是无限的.当我键入时3,它应该打印出来Thank you, Have a nice day.并退出循环while (option != 3).但是,似乎while循环不起作用.

我是一名c ++自学者,我正在经历这种奇怪的行为.

#include <iostream>
using namespace std;
int main () {
    for (int i=0;i<3;i++) {
        switch(i) {
            case '0' : // do something
                cout << "A" << endl;
            case '1' : // do something else
                cout << "B" << endl;
            // no default set
        }
    }
    return 0;
}

有了这个MWE,为什么不执行switch语句？在我的机器上,用g ++和cmake编译,我看到控制台上没有打印charachter.

谢谢你的帮助!