Variables and data types in C++

Variables and data types in C++

• 1.
  VARIABLES AND DATATYPES IICT – Lab-8 IN C++
• 2.
  VARIABLE • Portion ofMemory to Store a Value. • Each variable needs a unique name that distinguishes it from others. • Name of the variable should be a valid C++ Identifier. a=5; b=2; In this, variable names are ‘a’ and ‘b’
• 3.
  VARIABLE Memory 5 a=5; a Memory Location reserved Andnamed as “a”
• 4.
  IDENTIFIERS • A valididentifier is a sequence of one or more letters, digits or underscore “ _ “ • A valid identifier shall always begin with a letter or underscore “ _ “ • A valid identifier CAN’T contain Spaces, punctuation marks or any other symbols. • A valid identifier CAN’T start with a digit in any case. • A valid identifier CAN’T be a Reserved Keyword of C++
• 5.
  RESERVED KEYWORDS Following arereserved keywords of C++ and can’t be used as identifiers. alignas, alignof, and, and_eq, asm, auto, bitand, bitor, bool, break, case, catch, char, char16_t, char32_t, class, compl, const, constexpr, const_cast, continue, decltype, default, delete, do, double, dynamic_cast, else, enum, explicit, export, extern, false, float, for, friend, goto, if, inline, int, long, mutable, namespace, new, noexcept, not, not_eq, nullptr, operator, or, or_eq, private, protected, public, register, reinterpret_cast, return, short, signed, sizeof, static, static_assert, static_cast, struct, switch, template, this, thread_local, throw, true, try, typedef, typeid, typename, union, unsigned, using, virtual, void, volatile, wchar_t, while, xor, xor_eq
• 6.
  ARE THESE VALIDIDENTIFIERS? 1. A 2. result 3. temppp 4. 6B 5. B46_34a 6. a.jok 7. 0_klm 8. _7ab 9. aaaa 10._a_b_        X X X
• 7.
  Result result RESULTresulT C++ is a Case-Sensitive Language and so are its Identifiers. IDENTIFIERS
• 8.
  DATA TYPES • Character[ char ] • Integer [ int ] • Float [ float ] • Boolean [ bool ]
• 9.
  DECLARATION OF VARIABLES •Identifier for variable, followed by its data type. int a; float mynumber; • To declare more than one variables of same type, separate their identifiers with commas, in single statement. int a,b,c; int a; int b; int c; (It is exactly same as declaring variables like this)
• 10.
  INITIALIZATION OF VARIABLES •Assigning a value to the variable from the moment it is declared. int a=5; (value of a is 5) float mynumber=2.5; (value of mynumber is 2.5) int b; (value of b is undertermined)