Introduction to C + +: Literals: Integer, Character and Floating Constant, String Literals

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Literals

• Literals (often referred to as constants) are data items that never change their value during the execution of the program.

• The following types of literals are available in C++.

Integer Constants

• Integer constants are whole numbers without any fractional part.

• It may contain either + or – sign, but decimal point or commas does not appear in any integer constant.

• C++ allows three types of integer constants.

• Decimal (Base 10)

• Octal (Base 8)

• Decimal (Base 10)

• It consists of sequence of digits and should not begin with 0 (zero). For example, 124, - 179, + 108.

• Octal integer constants

• It consists of sequence of digits starting with 0 (zero). For example, 014, 012.

• It consists of sequence of digits preceded by ox or OX. For example, OXD, OXC. The suffix l or L and u or U attached to any constant forces it to be represented as a long and unsigned respectively.

Character-Constants

• A character constant in C++ must contain one or more characters and must be enclosed in single quotation marks.

• For example, ‘A’, ‘9’, etc. C++ allows nongraphic characters which cannot be typed directly from keyboard, e.g., backspace, tab, carriage return etc.

• These characters can be represented by using a escape sequence.

• An escape sequence represents a single character

• The following table gives a listing of common escape sequences.

Floating Constants

• They are also called real constants. They are numbers having fractional parts. They may be written in fractional from or exponent form

• A real constant in fractional form consists of signed or unsigned digits including a decimal point between digits. For example, 3.0, -17.0, -0.627 etc.

String Literals

• A sequence of character enclosed within double quotes is called a string literal.

• String literal is by default (automatically) added with a special character ‘\O’ which denotes the end of the string.

• Therefore, the size of the string is increased by one character. For example, “COMPUTER” will be represented as “COMPUTER\O” in the memory and its size is 9 characters.

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