What is braces in java

What is braces in java

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7 — Statements

7.1 Simple Statements

Each line should contain at most one statement. Example:

argv++; // Correct argc--; // Correct argv++; argc--; // AVOID! 

7.2 Compound Statements

Compound statements are statements that contain lists of statements enclosed in braces » < statements >«. See the following sections for examples.

• The enclosed statements should be indented one more level than the compound statement.
• The opening brace should be at the end of the line that begins the compound statement; the closing brace should begin a line and be indented to the beginning of the compound statement.
• Braces are used around all statements, even single statements, when they are part of a control structure, such as an if-else or for statement. This makes it easier to add statements without accidentally introducing bugs due to forgetting to add braces.

7.3 return Statements

A return statement with a value should not use parentheses unless they make the return value more obvious in some way. Example:

return;return myDisk.size(); return (size ? size : defaultSize); 

7.4 if, if-else, if else-if else Statements

The if-else class of statements should have the following form:

if (condition) if (condition) < statements; >else < statements; >if (condition) < statements; >else if (condition) < statements; >else

Note: if statements always use braces, <> . Avoid the following error-prone form:

if (condition) //AVOID! THIS OMITS THE BRACES <>!statement; 

7.5 for Statements

A for statement should have the following form:

for (initialization; condition; update)

An empty for statement (one in which all the work is done in the initialization, condition, and update clauses) should have the following form:

for (initialization; condition; update);

When using the comma operator in the initialization or update clause of a for statement, avoid the complexity of using more than three variables. If needed, use separate statements before the for loop (for the initialization clause) or at the end of the loop (for the update clause).

7.6 while Statements

A while statement should have the following form:

An empty while statement should have the following form:

7.7 do-while Statements

A do-while statement should have the following form:

7.8 switch Statements

A switch statement should have the following form:

Every time a case falls through (doesn’t include a break statement), add a comment where the break statement would normally be. This is shown in the preceding code example with the /* falls through */ comment.

Every switch statement should include a default case. The break in the default case is redundant, but it prevents a fall-through error if later another case is added.

7.9 try-catch Statements

A try-catch statement should have the following format:

try catch (ExceptionClass e)

A try-catch statement may also be followed by finally , which executes regardless of whether or not the try block has completed successfully.

try catch (ExceptionClass e) < statements; >finally

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What are braces for in Java?

Braces are used around all statements, even single statements, when they are part of a control structure, such as an if-else or for statement. This makes it easier to add statements without accidentally introducing bugs due to forgetting to add braces.

What is K & R style?

K&R style. When following K&R, each function has its opening brace at the next line on the same indentation level as its header, the statements within the braces are indented, and the closing brace at the end is on the same indentation level as the header of the function at a line of its own.

Do you need curly braces Java?

In a Java program, everything is subordinate to the top line — the line with class in it. To indicate that everything else in the code is subordinate to this class line, you use curly braces. Everything else in the code goes inside these curly braces.

What is Java code conventions?

The Java code conventions are defined by Oracle in the coding conventions document. In short, these conventions ask the user to use camel case when defining classes, methods, or variables. It is important to get used to and follow coding conventions, so that code written by multiple programmers will appear the same.

Where do you put curly braces?

Curly brackets and indent style We strongly recommend you format your curly brackets following Java conventions: Do not put a new line before an opening curly bracket. Always start a new line after an opening curly bracket. A closing curly bracket should always belong on a separate line, except for else statements.

Should curly braces be on their own line C++?

Camp Two: Opening Curly Braces on a Separate Line The biggest advantage to having the opening curly brace on a separate line is that the curly braces will always line up visually (assuming that we are also using good horizontal spacing in our code).

What is a Java style guide?

1 Introduction. This document serves as the complete definition of Google’s coding standards for source code in the Java™ Programming Language. Like other programming style guides, the issues covered span not only aesthetic issues of formatting, but other types of conventions or coding standards as well.

Do ELSE statements need brackets in Java?

If the true or false clause of an if statement has only one statement, you do not need to use braces (also called “curly brackets”). This braceless style is dangerous, and most style guides recommend always using them.

What are braces used for in coding?

Braces are used to group statements and declarations. The contents of a class or interface are enclosed in braces. Method bodies and constructor bodies are enclosed in braces. Braces are used to group the statements in an if statement, a loop, or other control structures.

What is the difference between a bracket and a brace?

Brackets are punctuation marks, which are vertically oriented lines with a special figure. Braces are simply a special type of brackets, which are also known as curly brackets. In common practice, they are used are in poetry and music, to mark repeats or joined lines.

Is K&R still relevant?

As long as you’re talking about the 2nd Edition, K&R is still very relevant. In fact, I would say it’s still the very best single book on C, both for learning, and for reference. That said, you should also get a copy of Harbison & Steele’s “C: A Reference Manual”.

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What do curly braces in Java mean by themselves?

What do those stand-alone curly braces after the first if statement mean?

Java Solutions

Solution 1 — Java

The only purpose of the extra braces is to provide scope-limit. The List copy will only exist within those braces, and will have no scope outside of them.

If this is generated code, I assume the code-generator does this so it can insert some code (such as this) without having to worry about how many times it has inserted a List copy and without having to worry about possibly renaming the variables if this snippet is inserted into the same method more than once.

Solution 2 — Java

I second what matt b wrote, and I’ll add that another use I’ve seen of anonymous braces is to declare an implicit constructor in anonymous classes. For example:

 List names = new ArrayList() < // I want to initialize this ArrayList instace in-line, // but I can't define a constructor for an anonymous class: < add("Adam"); add("Eve"); > >; 

Some unit-testing frameworks have taken this syntax to another level, which does allow some slick things which look totally uncompilable to work. Since they look unfamiliar, I am not such a big fan myself, but it is worthwhile to at least recognize what is going on if you run across this use.

Solution 3 — Java

I agree with the scope limit answer, but would add one thing.

Sometimes you see a construct like that in the code of people who like to fold sections of their code and have editors that will fold braces automatically. They use it to fold up their code in logical sections that don’t fall into a function, class, loop, etc. that would usually be folded up.

Solution 4 — Java

I’d actually guess that someone forgot an else statement.

There’s rarely a good reason to even bother with creating additional block scopes. In this, and most cases, it’s far more likely someone may have forgotten to type their control statement than it is that they were doing something clever.

Solution 5 — Java

They make an inner scope. Variable declared inside these braces is not visible outside of them. This also applies to C/C++.

Solution 6 — Java

Solution 7 — Java

Braces are also useful to reduce the scope in switch/case statements.

switch(foo) < case BAR: int i = . . case BAZ: int i = . // error, "i" already defined in scope > 

switch(foo) < case BAR:< int i = . . > case BAZ:< int i = . // OK > > 

Solution 8 — Java

I think they just define an unnamed level of scope.

Solution 9 — Java

They define a new scope which means that everything declared in this scope is not visible outside the curly braces.

Solution 10 — Java

The bring a scope, copy will not be visible outside of it, so you can declare another variable with same name later. And it can be gathered by the garbage collector right after you exit that scope. In this case copy serves as a temporary variable, so it is a good example.

Solution 11 — Java

As an interesting note: the braces actually enable a class of statements: declarations.

This is illegal: if(a) int f;

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