指针例题1

 1 #include <stdio.h>
 2 void minmax(int *a, int len, int *min, int *max);
 3 int main(void)
 4 {
 5     int a[] = {
 6         1,
 7         2,
 8         3,
 9         4,
10         5,
11         6,
12         7,
13         8,
14         9,
15         12,
16         13,
17         14,
18         16,
19         17,
20         21,
21         23,
22         55,
23     };
24     int min, max;
25     printf("main sizeof(a) = %d
", sizeof(a));
26     printf("main a = %p
", a);
27     minmax(a, sizeof(a) / sizeof(a[0]), &min, &max);
28     printf("a[0] = %d
", a[0]);
29     printf("min = %d, max = %d
", min, max);
30     int *p = &min;
31     printf("*p = %d
", *p);
32     printf("p[0] = %d
", p[0]);
33     printf("*a = %d
", *a);
34     return 0;
35 }
36 void minmax(int *a, int len, int *min, int *max)
37 {
38     printf("minmax sizeof(a) = %d
", sizeof(a));
39     printf("main a = %p
", a);
40     a[0] = 1000;
41     *min = *max = a[0];
42     for (int i = 1; i < len; i++)
43     {
44         if (a[i] < *min)
45         {
46             *min = a[i];
47         }
48         if (a[i] > *max)
49         {
50             *max = a[i];
51         }
52     }
53 }