布尔变量 java,什么是声明在Java中布尔变量的正确方法？

最新推荐文章于 2023-08-15 21:00:51 发布

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最新推荐文章于 2023-08-15 21:00:51 发布

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文章标签：布尔变量 java

博客探讨了在Java编程中是否需要预先初始化布尔变量`isMatch`的问题。作者指出，虽然初始化变量是一种常见做法，特别是在多种语言间切换时，以确保始终明确变量状态，但在该示例中，直接用`email1.equals(email2)`的结果赋值给`isMatch`也是可行的，不会影响代码运行。文章建议可以根据个人习惯和项目需求来决定是否初始化变量。

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I have just started learning Java. In the online course I am following, I am asked to try the following code:

String email1 = "meme@me.coh";

String email2 = "meme@me.com";

Boolean isMatch = false;

isMatch = email1.equals (email2);

if (isMatch == true){

System.out.println("Emails match");

}

else{

System.out.println("Emails don't match");

}

I don't understand why I'm asked to declare isMatch as false when on the next line i am comparing the email addresses and assigning the value to isMatch.

I've tried the following code which seems to work just the same:

String email1 = "meme@me.coh";

String email2 = "meme@me.com";

Boolean isMatch;

isMatch = email1.equals (email2);

if (isMatch == true){

System.out.println("Emails match");

}

else{

System.out.println("Emails don't match");

}

On the course it doesn't explain why I'm declaring isMatch as false first. Is there a reason why I must declare isMatch as false before comparing the email addresses?

解决方案

You don't have to, but some people like to explicitly initialize all variables (I do too). Especially those who program in a variety of languages, it's just easier to have the rule of always initializing your variables rather than deciding case-by-case/language-by-language.

For instance Java has default values for Boolean, int etc .. C on the other hand doesn't automatically give initial values, whatever happens to be in memory is what you end up with unless you assign a value explicitly yourself.

In your case above, as you discovered, the code works just as well without the initialization, esp since the variable is set in the next line which makes it appear particularly redundant. Sometimes you can combine both of those lines (declaration and initialization - as shown in some of the other posts) and get the best of both approaches, i.e., initialize the your variable with the result of the email1.equals (email2); operation.