switch-statement

问题 I've google'd a bit but I still feel to be lost. I am writing a CPU emulator in JavaScript (namely Z80 in me case, currently). There is a huge switch statement in its heart. Though I can run some benchmarks of course, I can't be sure about future JavaScript engines of different browsers (ok, nobody can be, I know, but somebody should have greater knowledge of javascript engines of different browsers here than me ...). Is it faster to use other constructs than switch statement? Like an array

问题 I have a switch case that evaluates each character from some input. The switch case evaluates spaces and tabs fine but when it goes to evaluate a line break I can't seem to find a case that it works with. for (int i = 0; i < input.length(); i++) { char curr = input.charAt(i); switch (curr) { case 'a': //does stuff break; . . . //space case case ' ': outputCode = outputCode + curr + " read \n"; break; //tab case case ' ': outputCode = outputCode + curr + " read \n"; break; //new line case, the

问题 All of the values below are doubles, yet switch requires a integer value. Is there anyway around this? switch(fivePercentValue){ case floor((5*fivePercentValue) / 100): fivePercent_.backgroundColor = [UIColor greenColor]; fivePercentLabel_.textColor = [UIColor greenColor]; break; case ceil((5*fivePercentValue) / 100): fivePercent_.backgroundColor = [UIColor greenColor]; fivePercentLabel_.textColor = [UIColor greenColor]; break; default: fivePercent_.backgroundColor = [UIColor redColor];

问题 All of the values below are doubles, yet switch requires a integer value. Is there anyway around this? switch(fivePercentValue){ case floor((5*fivePercentValue) / 100): fivePercent_.backgroundColor = [UIColor greenColor]; fivePercentLabel_.textColor = [UIColor greenColor]; break; case ceil((5*fivePercentValue) / 100): fivePercent_.backgroundColor = [UIColor greenColor]; fivePercentLabel_.textColor = [UIColor greenColor]; break; default: fivePercent_.backgroundColor = [UIColor redColor];

问题 I have the following if, else if, else construct and I am just curious how I could convert such as construct into a switch statement. var emailSubject = email.subject.toLowerCase(); if(emailSubject.indexOf("account request") >= 0){ //do acct req }else if(emailSubject.indexOf("accounts pending removal for") >= 0){ //do account removal }else if(emailSubject.indexOf("listserv application") >= 0){ //do listserv app }else if(emailSubject.indexOf("student organization webmaster transfer request") >

问题 What is the reason behind the fact thet switch statements in C++ have to be written with constants? Let's take a look at the following code: switch(variable) { case 1: case 2: case 3: case 4: //Code 1 break; case 5: case 6: case 7: case 8: //Code 2 break; default: //Code 3 break; } In other languages, for example PAWN (C-Like scripting language), I could write this code down as such: switch(variable) { case 1 .. 4: //Code 1 break; case 5 .. 8: //Code 2 break; default: //Code 3 break; } What

问题 So for a college lab for Java Fundamentals I'm having trouble. I have to set up a switch and inside that switch a case. There are 3 options for user input, and each option can be answered with letter. The problem is that this letter is allowed to be capital OR lower case, and the problem is I cant seem to figure out how to set it up so a case will allow either of those. In the code below..crustType is defined as a char. Keep in mind this is Java Fundamentals and we're just learning about

问题 This is a SQL Server Integration Services (SSIS) expressions question (I'm pretty new to it). I would like to write a switch/case expression in a Derived Column transform - basically the new column can have 5 different possible values, based on the value of an input column. All I got from Google is the (condition) ? (true value) : (false value) technique, but this only provides for two possible values. Does SSIS expressions have a switch/case type expression? I thought of using sequential

问题 This is a SQL Server Integration Services (SSIS) expressions question (I'm pretty new to it). I would like to write a switch/case expression in a Derived Column transform - basically the new column can have 5 different possible values, based on the value of an input column. All I got from Google is the (condition) ? (true value) : (false value) technique, but this only provides for two possible values. Does SSIS expressions have a switch/case type expression? I thought of using sequential

问题 I want to use design pattern for this switch - case code. I tried to use the command pattern, but I could not understand how(I was programming only 2 for months) I wrote this program to learn how to better program. My code: public class Server { private static final String READ_NEW_MESSAGES = "read new mes"; private static final String SEND_PRIVATE_MESSAGES = "send mes"; private static final String JOIN_CHAT = "find chat"; private static final String CREATE_CHAT = "chating"; private static