cpp: 指针数组和数组指针

 1 #include <iostream>
 2 
 3 using std::cout, std::endl;
 4 
 5 void init(int* array)
 6 {
 7     for(int i=0; i<10; i++)
 8     {
 9         array[i]=i;    
10     }
11 }
12 
13 // print: output an array with 2 elements of type of int
14 void print(int (*p)[2])
15 {
16     cout << "output: ";
17     for(int i=0; i<5;i++)
18     {
19         int *p2=p[i];
20         for(int j=0; j<2; j++)
21         {
22             cout << p2[j] << ' ' ;
23         }
24     }
25     cout << endl;
26 }
27 
28 void msg()
29 {
30     // array: ten pointers of type of int
31     int *a[10];
32     
33     int aa[5][2] = {
34         1,2,
35         3,4,
36         5,6,
37         7,8,
38         9,0
39         };
40     
41      int (*ppt)[2]=aa;
42     
43     // ppt is pointer, ppt points an array with 2 elements of type of int
44     //
45     // ppt = { aa[0], aa[1], aa[2], aa[3], aa[4]}
46     // aa[0] = {aa[0][0], aa[0][1]}
47     // aa[1] = {aa[1][0], aa[1][1]}
48     // aa[2] = {aa[2][0], aa[2][1]}
49     // aa[3] = {aa[3][0], aa[3][1]}
50     // aa[4] = {aa[4][0], aa[4][1]}
51   
52     int i[10];
53     init(i);
54     
55     a[9] = &i[9];
56     
57     cout << "i[9] = " << i[9] << endl;
58     cout << "a[9] = " << *a[9] << endl;
59     
60     print(ppt);
61 }
62 
63 
64 int main()
65 {
66 
67    msg();
68    
69    return 0;
70 }

1 g++ -std=c++20 -O2 -Wall -pedantic -pthread main.cpp && ./a.out
2 
3 i[9] = 9
4 a[9] = 9
5 output: 1 2 3 4 5 6 7 8 9 0