What is the use of Static local variable when we can get a global variable at the same cost?

Question

In C ,what is the use of static storage class when an external variable can serve its purpose at the same cost ie. both occupy storage space in the data segment of the execu

Answer 1

A global variable is well, global, it can be accessed from anywhere.

A static local variable has local scope. It is static, so it's lifetime runs across the lifetime of the application however it can only be accessed from the local scope (whether that scope is a function, a block, or a file)