第 10 章 数组和指针

 1 /*---------------------------------
 2     array2d.c -- 处理二维数组的函数
 3 ---------------------------------*/
 4 
 5 #include <stdio.h>
 6 #define ROWS 3
 7 #define COLS 4
 8 
 9 void sum_rows(int ar[][COLS], int rows);
10 void sum_cols(int [][COLS], int);
11 int sum2d(int (*ar)[COLS], int rows);
12 
13 int main()
14 {
15     int junk[ROWS][COLS] =
16     {
17         {2, 4, 6, 8},
18         {3, 5, 7, 9},
19         {12, 10, 8, 6}
20     };
21 
22     sum_rows(junk, ROWS);
23     sum_cols(junk, ROWS);
24     printf("Sum of all elements = %d\n", sum2d(junk, ROWS));
25 
26     return 0;
27 }
28 
29 void sum_rows(int ar[][COLS], int rows)
30 {
31     for (int r(0); r != rows; ++r)
32     {
33         int total(0);
34         for (int c(0); c != COLS; ++c)
35             total += ar[r][c];
36         printf("row %d: sum = %d\n", r, total);
37     }
38 }
39 
40 void sum_cols(int ar[][COLS], int rows)
41 {
42     for (int c(0); c != COLS; ++c)
43     {
44         int total(0);
45         for (int r(0); r != rows; ++r)
46             total += ar[r][c];
47         printf("col %d: sum = %d\n", c, total);
48     }
49 }
50 
51 int sum2d(int ar[][COLS], int rows)
52 {
53     int total(0);
54 
55     for(int r(0); r != rows; ++r)
56         for(int c(0); c != COLS; ++c)
57             total += ar[r][c];
58 
59     return total;
60 }