by Dinesh Thakur Category: Type And Variables

Declaration of a variable in C hints the compiler about the type and size of the variable in compile time. Similarly, declaration of a function hints about type and size of function parameters. No space is reserved in memory for any variable in case of declaration.

Example: int a;
Here variable 'a' is declared of data type 'int'

Defining a variable means declaring it and also allocating space to hold it.

We can say "Definition = Declaration + Space reservation".
Example: int a = 10;

Here variable "a" is described as an int to the compiler and memory is allocated to hold value 10.

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Dinesh ThakurDinesh Thakur holds an B.C.A, MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.