Detailed Explanation of C++ Scoping: Differences Between Local and Global Variables

In C++, a scope is the "active range" of a variable, i.e., the code region where the variable can be accessed. It is mainly divided into local variables and global variables. Local variables are defined inside a function or a code block (e.g., if, for blocks). Their scope is limited to the area where they are defined. Their lifecycle starts when the function is called and ends when the function exits. They are stored in the stack, and uninitialized local variables will have random values. Global variables are defined outside all functions. Their scope spans the entire program, with a lifecycle from program startup to termination. They are stored in the global data area and require careful usage (as they are prone to being modified by multiple functions, leading to logical issues). Core differences: Local scope is small, uses stack memory, and is temporary; global scope is large, uses global data area memory, and is long-lived. When names conflict, local variables take precedence, and global variables can be accessed using `::`. Note: Local variables should be initialized. For global variables shared across multiple files, use `extern` for declaration. Reasonably plan variable scopes, prioritizing local variables and using global variables only when necessary.