Parameter has a two-dimensional array

The Declaration function has the following void function (int** p), which is intended to pass a two-dimensional array to the parameter. A two-dimensional array is defined, such as int a[1][1], and then the function is called. What's the result? Of course it failed, compiler tip: cannot convert parameter 1 from ' int [1][1] ' to ' int * *, parameter types do not match. I have tried the above process myself, of course, does not match, the type is completely different. Then I thought: if you want to use a two-dimensional array as a formal parameter, what is the function to declare?

Simple point

Array name as formal parameter

void func1 (int array[][]) {}int  main () {    int array[] [ten];    Func1 (array);}

Compile, note that the formal parameter declaration must give the size of the second dimension, or compile.

One-dimensional array pointers as formal parameters

void func2 (int (*parray) [ten]) {}void func2_1 (int// compilation passed, cannot be called, the second dimension is not given {}int  main () {    int array[] [ten];    Func2 (array);}

In fact, the two-dimensional array name is a pointer to a one-dimensional array, so this way of declaring OK. You must specify the length of a one-dimensional array, and if not specified, the function declaration is compiled. But if there is a calling code, there will be no compilation, because no argument type can match int[].

Two-dimensional array references as formal parameters

void func3 (int (&parray) [ten] [ten]) {}int  main () {     int array[] [ten];    FUNC3 (array);}

You must specify a length of two dimensions.

Two-dimensional array pointers as formal parameters

void func4 (int (*parray) [ten] [ten]) {}int  main () {     int array[] [ten];    Func4 (&array);}

You must specify a length of two dimensions

Back to the question that was mentioned earlier in this article: can you accept two-dimensional array arguments using double pointer int** as a formal parameter? The answer is yes, but it's limited. With a double pointer as a formal parameter, the corresponding argument is also a double pointer. In fact, this double pointer actually points to an array of pointers, double pointers are declared in a way that is ideal for passing a two-dimensional array of dynamic (that is, the dimension is a variable) created. How to create a two-dimensional array dynamically? The following programs:

void func5 (intint  n) {  }  int  main () {     int  n=10;    int **a=newint *[n];       for (int i=0; i<n;i++)        a[i]=newint[n];}

Parameter has a two-dimensional array