- Dev C++ Character Setup
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Each variable in C has a specific type, which determines the size and layout of the variable's memory; the range of values that can be stored within that memory; and the set of operations that can be applied to the variable. The name of a variable can be composed of letters, digits, and the underscore character. Jun 16, 2011 Assuming you did that you probably have have Chinese characters in your source code. To display them correctly you need to change the default Dev C codepage to windows-936 (Chinese simplified) or windows-950 (Chinese traditional). This is the codepage for the file which is independent of the system setting. Senior Software Development Engineer Microsoft Visual C. A set of characters, not glyphs (so, not concerned with visual representation) Unicode 1.0 Each character is mapped to a 16-bit code point Up to 65,536 characters can be represented (in theory; fewer in practice). C Character Set In C, character set is a set of all valid characters that can be used in a C Program. Characters set is used to specify the characters or symbols recognized by the language. Character set is a set of all valid characters that can be used to form words, numbers and expression’s in.
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A variable provides us with named storage that our programs can manipulate. Each variable in C++ has a specific type, which determines the size and layout of the variable's memory; the range of values that can be stored within that memory; and the set of operations that can be applied to the variable.
The name of a variable can be composed of letters, digits, and the underscore character. It must begin with either a letter or an underscore. Upper and lowercase letters are distinct because C++ is case-sensitive −
There are following basic types of variable in C++ as explained in last chapter −
Sr.No | Type & Description |
---|---|
1 | bool Stores either value true or false. |
2 | char Typically a single octet (one byte). This is an integer type. |
3 | int The most natural size of integer for the machine. |
4 | float A single-precision floating point value. |
5 | double A double-precision floating point value. |
6 | void Represents the absence of type. |
7 | wchar_t A wide character type. |
C++ also allows to define various other types of variables, which we will cover in subsequent chapters like Enumeration, Pointer, Array, Reference, Data structures, and Classes.
Dev C++ Character Setup
Following section will cover how to define, declare and use various types of variables.
Variable Definition in C++
A variable definition tells the compiler where and how much storage to create for the variable. A variable definition specifies a data type, and contains a list of one or more variables of that type as follows −
Here, type must be a valid C++ data type including char, w_char, int, float, double, bool or any user-defined object, etc., and variable_list may consist of one or more identifier names separated by commas. Some valid declarations are shown here −
The line int i, j, k; both declares and defines the variables i, j and k; which instructs the compiler to create variables named i, j and k of type int.
Variables can be initialized (assigned an initial value) in their declaration. The initializer consists of an equal sign followed by a constant expression as follows −
Some examples are −
For definition without an initializer: variables with static storage duration are implicitly initialized with NULL (all bytes have the value 0); the initial value of all other variables is undefined.
Variable Declaration in C++
A variable declaration provides assurance to the compiler that there is one variable existing with the given type and name so that compiler proceed for further compilation without needing complete detail about the variable. A variable declaration has its meaning at the time of compilation only, compiler needs actual variable definition at the time of linking of the program.
A variable declaration is useful when you are using multiple files and you define your variable in one of the files which will be available at the time of linking of the program. You will use extern keyword to declare a variable at any place. Though you can declare a variable multiple times in your C++ program, but it can be defined only once in a file, a function or a block of code.
Example
Try the following example where a variable has been declared at the top, but it has been defined inside the main function −
When the above code is compiled and executed, it produces the following result −
Same concept applies on function declaration where you provide a function name at the time of its declaration and its actual definition can be given anywhere else. For example −
Lvalues and Rvalues
There are two kinds of expressions in C++ −
- lvalue − Expressions that refer to a memory location is called 'lvalue' expression. An lvalue may appear as either the left-hand or right-hand side of an assignment.
- rvalue − The term rvalue refers to a data value that is stored at some address in memory. An rvalue is an expression that cannot have a value assigned to it which means an rvalue may appear on the right- but not left-hand side of an assignment.
Dev C++ Character Settings
Variables are lvalues and so may appear on the left-hand side of an assignment. Numeric literals are rvalues and so may not be assigned and can not appear on the left-hand side. Following is a valid statement −
But the following is not a valid statement and would generate compile-time error −
Dev C++ Character Setting
![C++ C++](/uploads/1/2/6/1/126159174/497964314.png)
Lets you specify the source character set for your executable.
Dev C++ Character Sets
Syntax
Arguments
IANA_name
The IANA-defined character set name.
The IANA-defined character set name.
CPID
The code page identifier as a decimal number.
The code page identifier as a decimal number.
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Remarks
You can use the /source-charset option to specify an extended source character set to use when your source files include characters that are not represented in the basic source character set. The source character set is the encoding used to interpret the source text of your program into the internal representation used as input to the preprocessing phases before compilation. The internal representation is then converted to the execution character set to store string and character values in the executable. You can use either the IANA or ISO character set name, or a dot (.) followed by a 3 to 5 digit decimal code page identifier to specify the character set to use. For a list of supported code page identifiers and character set names, see Code Page Identifiers.
By default, Visual Studio detects a byte-order mark to determine if the source file is in an encoded Unicode format, for example, UTF-16 or UTF-8. If no byte-order mark is found, it assumes the source file is encoded using the current user code page, unless you specify a character set name or code page by using the /source-charset option. Visual Studio allows you to save your C++ source code by using any of several character encodings. For more information about source and execution character sets, see Character Sets in the language documentation.
The source character set you supply must map the 7-bit ASCII characters to the same code points in your character set, or many compilation errors are likely to follow. Your source character set must also be mappable to the extended Unicode character set encodable by UTF-8. Characters that are not encodable in UTF-8 are represented by an implementation-specific substitute. The Microsoft compiler uses a question mark for these characters.
If you want to set both the source character set and the execution character set to UTF-8, you can use the /utf-8 compiler option as a shortcut. It is equivalent to specifying /source-charset:utf-8 /execution-charset:utf-8 on the command line. Any of these options also enables the /validate-charset option by default.
To set this compiler option in the Visual Studio development environment
- Open the project Property Pages dialog box. For more information, see Set C++ compiler and build properties in Visual Studio.
- Expand the Configuration Properties, C/C++, Command Line folder.
- In Additional Options, add the /source-charset option, and specify your preferred encoding.
- Choose OK to save your changes.
See also
MSVC Compiler Options
MSVC Compiler Command-Line Syntax
/execution-charset (Set Execution Character Set)
/utf-8 (Set Source and Executable character sets to UTF-8)
/validate-charset (Validate for compatible characters)
MSVC Compiler Command-Line Syntax
/execution-charset (Set Execution Character Set)
/utf-8 (Set Source and Executable character sets to UTF-8)
/validate-charset (Validate for compatible characters)