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diff --git a/docs/source/lang/cpp/curly-braces.rst b/docs/source/lang/cpp/curly-braces.rst new file mode 100644 index 0000000..a4bd3dc --- /dev/null +++ b/docs/source/lang/cpp/curly-braces.rst @@ -0,0 +1,109 @@ +.. highlight:: cpp + +.. _lang-curly-braces: + +Curly Braces (``{``, ``}``) +=========================== + +.. contents:: Contents + :local: + +Introduction +------------ + +Curly braces (also referred to as just "braces" or as "curly +brackets") are a major part of the C and C++ programming +languages. 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 Maple 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 companion will be highlighted\ +[#fbug]_\ . + +Beginning programmers, and programmers coming to C++ from languages +without braces, often find using them confusing or daunting. + +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 blank lines 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 +usually dramatically affect the meaning of a program. + +The main uses of curly braces +----------------------------- + +**Functions**:: + + // a function body needs braces around it + void myFunction(datatype argument) { + // ... function body goes in here ... + } + +**Loops** (see the :ref:`while <lang-while>`\ , :ref:`for +<lang-for>`\ , and :ref:`do/while <lang-dowhile>` loop reference +pages for more information):: + + // you should put braces around the body of a loop: + + while (boolean expression) { + // code inside the loop goes here + } + + for (initialisation; termination condition; incrementing expr) { + // code inside the loop goes here + } + + do { + // code inside the loop goes here + } while (boolean expression); + + +**Conditional statements** (see the :ref:`if statement <lang-if>` +reference page for more information):: + + // you should put braces around the body of an "if", "else if", + // or "else": + + if (boolean expression) { + // code inside the "if" + } + else if (boolean expression) { + // code inside the "else if" + } + else { + // code inside the "else" + } + +**Switch statements** (see the :ref:`switch statement +<lang-switchcase>` reference page for more information):: + + switch (var) { + case 1: + doThing1(); + break; + case 2: + doThing2(); + break; + } + +.. rubric:: Footnotes + +.. TODO remove this once IDE 0.1.0 released + +.. [#fbug] At present this feature is slightly buggy as the IDE will + often find (incorrectly) a brace in text that has been commented + out. + + +.. include:: cc-attribution.txt |