en:reference:language:braces
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| ====== {} Curly Braces ====== |
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| 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. |
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| 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 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. |
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| At present this feature is slightly buggy as the IDE will often find (incorrectly) a brace in text that has been "commented out." |
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| 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. |
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| 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. |
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| 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. |
| ===== The main uses of curly braces ===== |
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| ==== Functions ==== |
| <code cpp> |
| void myfunction(datatype argument){ |
| statements(s) |
| } |
| </code> |
| ==== Loops ==== |
| <code cpp> |
| while (boolean expression) |
| { |
| statement(s) |
| } |
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| do |
| { |
| statement(s) |
| } |
| while (boolean expression); |
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| for (initialisation; termination condition; incrementing expr) |
| { |
| statement(s) |
| } |
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| </code> |
| ==== Conditional statements ==== |
| <code cpp> |
| if (boolean expression) |
| { |
| statement(s) |
| } |
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| else if (boolean expression) |
| { |
| statement(s) |
| } |
| else |
| { |
| statement(s) |
| } |
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| </code> |
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en/reference/language/braces.txt · 最后更改: 2023/06/07 04:23 由 127.0.0.1