? Scope in C

Scope in C refers to the visibility and lifetime of variables — i.e., where a variable can be accessed in your code.

There are 4 types of scope in C:

? 1. Block Scope (Local Scope)

Variables declared inside a block (like in functions or {}) are accessible only within that block.

c
() {    int x = 10;  // x has block scope    printf("%d", x);}

• x is local to myFunction()

• Cannot be accessed outside the block

? 2. Function Scope

Applies to labels (used with goto) inside a function. Rarely used.

c
void func() {    goto label;    label: printf("Hello\n");}

? 3. File Scope (Global Scope)

Variables declared outside all functions are global — accessible anywhere in the file after declaration.

c
int count = 0;  // global variablevoid display() {    printf("%d\n", count);  // accessible here}

? 4. Function Prototype Scope

In function declarations:

c
void fun(int a); // `a` is only known inside this declaration

This a only exists for declaration purposes.

? Storage Class Keywords & Scope

?? Tips

• ? Keep variables local if possible — it avoids bugs.

• ? Use static inside functions if you need the value to persist between calls.

• ? Avoid unnecessary global variables.