THINK++ — Engineering Visualized

05 // Storage

Variables

A variable is a named memory location that stores data. Every variable in C++ must be declared with a type before use.

Declaration & Initialization

Declarationint age;Reserves memory without assigning a value

Initializationint age = 25;Declares and assigns in one step

Multipleint a = 1, b = 2, c = 3;Multiple variables of the same type

Constantconst int MAX = 100;Value cannot be changed after initialization

Naming Rules

✓Must start with a letter or underscoreint _count = 0;

✗Cannot use C++ reserved keywordsint class = 5;

✓Case-sensitive namingint Age ≠ int age

✗No spaces or special charactersint my var = 1;

Uninitialized local variables contain garbage values. Always initialize your variables to avoid undefined behavior in your programs.

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