当局部变量遇上全局变量——extern及花括号用法举例

 1 #include <stdio.h>
 2 
 3 int val = 9;
 4 
 5 int foo()
 6 {
 7     int val = 2; 
 8     {
 9         extern int val;
10         printf("val_foo = %d\n", val);
11     }
12     return val;
13 }
14 
15 int main()
16 {
17     int val = 0;
18     printf("val_main1 = %d\n", val);
19     val = foo();
20     printf("val_main2 = %d\n", val);
21     system("pause");
22     return val;
23 }