{}

[Further Syntax]

描述

Curly braces (also referred to as just “braces” or as “curly brackets”) are a major part of the C programming language. They are used in several different constructs, outlined below, and this can sometimes be confusing for beginners.

An opening curly brace “{” must always be followed by a closing curly brace “}”. This is a condition that is often referred to as the braces being balanced. The 86Duino IDE (integrated development environment) includes a convenient feature to check the balance of curly braces. Just select a brace, or even click the insertion point immediately following a brace, and its logical companion will be highlighted.

At present this feature is slightly buggy as the IDE will often find (incorrectly) a brace in text that has been “commented out.”

Beginning programmers, and programmers coming to C from the BASIC language often find using braces confusing or daunting. After all, the same curly braces replace the RETURN statement in a subroutine (function), the ENDIF statement in a conditional and the NEXT statement in a FOR loop.

Because the use of the curly brace is so varied, it is good programming practice to type the closing brace immediately after typing the opening brace when inserting a construct which requires curly braces. Then insert some carriage returns between your braces and begin inserting statements. Your braces, and your attitude, will never become unbalanced.

Unbalanced braces can often lead to cryptic, impenetrable compiler errors that can sometimes be hard to track down in a large program. Because of their varied usages, braces are also incredibly important to the syntax of a program and moving a brace one or two lines will often dramatically affect the meaning of a program.

Example Code

Functions

void myfunction(datatype argument){
  statements(s)
}

Loops

while (boolean expression)
{
   statement(s)
}
 
do
{
   statement(s)
} while (boolean expression);
 
for (initialisation; termination condition; incrementing expr)
{
   statement(s)
} 

Conditional statements

if (boolean expression)
{
   statement(s)
}
 
else if (boolean expression)
{
   statement(s)
} 
else
{
   statement(s)
}

語法參考主頁面

86Duino 參考的文本是根據 Creative Commons Attribution-ShareAlike 3.0 License，部分文本是從 the Arduino reference 修改的。 參考中的代碼示例已發佈到公共領域。