c语言中可以在函数内改变全局变量的值

 1 #include<stdio.h>
 2 int global_value=9;
 3 void change(void)
 4 {
 5     global_value=8;
 6 }
 7 void main()
 8 {
 9     printf("before:  global_value=%d",global_value );
10     printf("\n");
11     change();
12     printf("after:   global_value=%d",global_value);
13 
14 }