C语言和指针-回顾16-预处理指令 #argument和##

#argument：它被预处理翻译为argument

##：把自己两边的符号连接成一个符号

 1 #include<stdio.h>
 2 
 3 static int global_status_1 = 0;
 4 static int global_status_2 = 0;
 5 
 6 #define MY_PRINT(FORMAT, VALUE) 
 7     printf("The value of " #VALUE " is " FORMAT "
", VALUE)
 8 
 9 #define UPDATE_GLOBAL_STATUS(INDEX, VALUE) 
10     (global_status_ ## INDEX = VALUE); 
11     printf("global_status_"#INDEX " is %d
", global_status_ ## INDEX )
12 
13 int main()
14 {
15     int x = 5;
16     MY_PRINT("%d",x+10);
17     UPDATE_GLOBAL_STATUS(1, 5);
18     UPDATE_GLOBAL_STATUS(2, 6);
19     printf("global_status_1=%d
", global_status_1);
20     printf("global_status_2=%d
", global_status_2);
21 }
22 #include<stdio.h>
23 
24 static int global_status_1 = 0;
25 static int global_status_2 = 0;
26 
27 #define MY_PRINT(FORMAT, VALUE) 
28     printf("The value of " #VALUE " is " FORMAT "
", VALUE)
29 
30 #define UPDATE_GLOBAL_STATUS(INDEX, VALUE) 
31     (global_status_ ## INDEX = VALUE); 
32     printf("global_status_"#INDEX " is %d
", global_status_ ## INDEX )
33 
34 int main()
35 {
36     int x = 5;
37     MY_PRINT("%d",x+10);
38     UPDATE_GLOBAL_STATUS(1, 5);
39     UPDATE_GLOBAL_STATUS(2, 6);
40     printf("global_status_1=%d
", global_status_1);
41     printf("global_status_2=%d
", global_status_2);
42 }

Output:

The value of x+10 is 15
global_status_1 is 5
global_status_2 is 6
global_status_1=5
global_status_2=6