"Dark Horse programmer" Local variables and global variables (C language)

depending on the scope of the variable, it can be divided intoLocal Variables:

Definition: A variable defined inside a function or code block

Scope: Start with the line that defines the variable until the end of the code block

Declaration period: Allocates storage space from the line that defines the face, which is recycled after the code block is finished

No fixed initial value

Global Variables:

Definition: A variable defined outside a function

Scope: Starts from the line that defines the variable, until the end of the file (all functions can be shared)

Declaration period: Allocates storage space from the row that defines the variable and is destroyed when the program exits

The default disposition is 0.

Code Exercise:

#include <stdio.h>    int age;                        Define global Variables Agevoid test () {Age  = 10;} int main () {  printf ("Age =%d\n", age);       Output age = 0  test ();  printf ("Age =%d\n", age);       Output Age = 10  

The first output is 0, because there is no age variable within the main function and age outside the main function is a global variable, and it is not initialized, so the default value of 0 is maintained.

The second output is ten; the test function finishes executing the age variable and is destroyed, and the global variable is accessed here

"Dark Horse programmer" Local variables and global variables (C language)