C中的数组数组

Question

你如何声明一个数组数组？ 假设我有一个数组s[] 。 s[0]将包含另一个数组a[]而a[0]将包含数组b[] 。 你会用指针做什么？

Answer 1

// b is an array of int.  (N is some number.)
int b[N];

// a Option 0:  a is an array of M arrays of N int.  (M is some number.)
int a[M][N];

// a Option 1:  a is an array of M pointers to int.
int *a[M];
a[0] = b;
// Other elements of a must also be assigned in some way.

// s Option 0:  s is an array of L arrays of M arrays of N int.  (L is some number.)
int s[L][M][N];

// s Option 1:  s is an array of L arrays of M pointers to int.
int *s[L][M];
s[0][0] = b;
// Other elements of s must also be assigned in some way.

// s Option 2:  s is an array of L pointers to arrays of N int.
int (*s[L])[N];
s[0] = a; // Can use a from a Option 0, not a from a Option 1.
// Other elements of s must also be assigned in some way.

// s Option 3:  s is an array of L pointers to pointers to int.
int **s[L];
s[0] = a; // Can use a from a Option 1, not a from a Option 0.
// Other elements of s must also be assigned in some way.

还有一些选项，其中每个对象都是最高级别的指针，而不是数组。 我没有表现出来。 他们需要为指针指定一些内容。

Answer 2

一个简单的方法。

int length = 10;

int b[5] = {0,1,2,5,4};

int c[7] = {1,2,3,4,5,6,7};

int** s = malloc(sizeof(int*) * length);

s[1] = b;
s[2] = c; 

等等...

此示例适用于2层。 使指针s是***s和适当的修改，以使其3层。