What is the role and application of the static keyword in programming?

In C/C++, the keyword static has several uses related to the scope and lifetime of variables and functions:

1. Inside a function:
   • A variable declared as static retains its value between function calls.
   • It is initialized only once.

void func() {
    static int count = 0;
    count++;
    std::cout << count << std::endl;
}
// Each call to func() increases count, and the value is preserved between calls.

2. Inside a file (global scope):
   • static limits the scope of a function or variable to the current file (translation unit).
   • This prevents name conflicts during linking.

static void helper() {
    // This function is only visible within this file
}

3. In a class (C++):
   • static class members belong to the class itself, not to any specific object.
   • Shared among all instances.

class MyClass {
public:
    static int count;
};
int MyClass::count = 0;

Thus, static manages the lifetime, scope, and ownership of variables and functions.