C Storage Classes:

In C, Storage Classes are used to define the scope (visibility), lifetime, and initial value of variables and functions. By telling the compiler where to store a variable and how long it should exist, you can write more memory-efficient and organized code.

1. The Four Standard Storage Classes

C provides four primary storage classes, each serving a specific purpose in memory management:

2. auto: The Default Class

The auto storage class is the default for all local variables. It is rarely written explicitly because variables declared inside a function are automatically "auto."

3. static: Preserving Values

A static variable remains in memory until the program ends. If declared inside a function, it "remembers" its value between different function calls.

4. register: High-Speed Access

The register keyword suggests to the compiler that the variable be stored in a CPU register instead of RAM for faster access. This is used for variables used frequently, like loop counters.

5. extern: Global Linkage

The extern storage class is used when a variable is defined in one file but needs to be accessed in another. It tells the compiler, "This variable exists somewhere else."

6. Scope vs. Lifetime

• Scope: The region of the code where the variable can be accessed (e.g., Local or Global).
• Lifetime: The duration for which the variable stays in the computer's memory.