Scope

In C, scope defines the region of a program where a variable can be accessed. Variables in C are categorized into local and global scopes based on their accessibility.

Local Scope

Variables declared inside a function or block have local scope, meaning they are accessible only within that function or block.

Syntax for local scope

return_type function_name() {
    // Variable with local scope
    data_type variable_name = value;

    // Code that uses the variable
    ...
}

• data_type: Represents the type of the variable.
• variable_name: Name of the variable used in the code.
• value: Value assigned to the variable.

Global Scope

Variables declared outside of any function have global scope and can be accessed and modified from any function within the program.

Syntax for global scope

data_type variable_name = value;
// Global variable (declared outside any function)
return_type function_name() {
    // Code that can access the global variable
}

Example

The example demonstrates variable scope in C, where globalVar has global scope (accessible throughout the program), while localVar has local scope (accessible only within myFunction):

#include <stdio.h>
// Global variable
int globalVar = 100;
void myFunction() {
    // Local variable
    int localVar = 10;

    // Accessing both local and global variables
    printf("Local variable inside myFunction: %d\n", localVar);
    printf("Global variable inside myFunction: %d\n", globalVar);
}
int main() {
    // Accessing the global variable
    printf("Global variable inside main: %d\n", globalVar);

    // Calling the function which accesses both local and global variables
    myFunction();

    return 0;
}

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The code above produces this output:

Global variable inside main: 100
Local variable inside myFunction: 10
Global variable inside myFunction: 100

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