Pointer array & array pointer

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arr[i] == *(arr+i);
arr[i][j] == *(*(arr+i)+j) == *(arr[i]+j)

     

      
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About arr[i][j] The understanding of the

*(*(arr+i)+j) == arr[i][j]

(arr+i): Is to find the first i The address of a location

*(arr+i)： Find No. in the pointer array i Elements of position , This element is an array name

*(*(arr+i)+j): By array name ( The address of the first element of the array ) The offset j Length , You can find the starting position of the array name by dereferencing j Location data

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Pointer array stores the name of character array

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int main()
{
    const char* arr[5] = {"abcdef","bcdefg","hehe","haha","zhangs"};
    //arr Arrays store constant strings , So use const Modify the array 
    int i= 0;
    for(i = 0;i<5;i++)
    {
        printf("%s\n",arr[i]);
    }
    return 0;
}

     

      
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To print a string, you only need to provide the starting address , Print backwards from the starting position Print shaping requires dereference to get the value inside

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int* arr[5]	// Pointer array 
//arr It's an array name , The array name is the first element address ,int** type 

     

      
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 The array name of pointer array is stored with secondary pointer 
   int* arr[5];
int** p = arr;
// amount to int**p = &arr[0] 
int** p2 = &arr[3];

     

      
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4. Array pointer - Is a pointer

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int a = 10;
int* pi = &a;	// The reshaped address is stored in the reshaped pointer 
char ch = 'w';
char* pc = ch;// The address of the character is stored in the character pointer 

     

      
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How to write array pointers

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//int *parr[10] :parr The first and [] combination , It's an array , Array element type is integer pointer 

 // If you want to parr Is a pointer -> Enclosed in brackets 
int (*parr)[10] = &arr;	// What we get is the address of the array , It should be stored in the array pointer 

//int（*parr）[10] ：parr The first and * combination , Is a pointer , It's an array , Array has 10 Elements , Each element is int type 

     

      
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int* arr[10] = {0};
int* (*p)[10] = &arr;	// Take the address of the array and put it into the array pointer 
int** p = arr;	// The array element is ：int* type . The array name is the first element address , The type is ：int**

//arr The type of ：int*
//&arr[0] The type of ：int*
//&arr The type of ：int(*)[10]

     

      
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The type of pointer determines how many bytes it skips by adding or subtracting integers

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 The array name is the first element address    There are two exceptions 
1. The array list is placed alone in sizeof Inside 
   sizeof( Array name ), The array name expression here is the whole array , It calculates the size of the entire array 
2.& Array name 
  At this time, the array name identifies the entire array , It takes out the address of the entire array ,
    &arr+1 : Skip the contents of an array 

     

      
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Array name when transferring parameters , Will be demoted to the first element address

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void Print1(int arr[],int sz);
void Print2(int* arr,int sz);
// The above two expressions are equivalent 

     

      
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