基于指针的查询

Question

#include<iostream.h>
void main()
{
    int arr[2][3][2]={{{2,4},{7,8},{3,4},}, {{2,2},{2,3},{3,4}, }};
    cout<<**(*arr+1)+2+7;
}

According to me answer will be 11, But compiler is showing 16. Can anyone please explain the solution? Thanks in advance

Answer 1

*arr is equivalent to arr[0] .

*(arr[0]+1) is equivalent to arr[0][1] .

*arr[0][1] is equivalent to arr[0][1][0] .

So, your code is equivalent to this:

#include<iostream.h>

void main()
{
    int arr[2][3][2]={
      {{2,4},{7,8},{3,4},},
      {{2,2},{2,3},{3,4},}
    };
    cout << arr[0][1][0]+2+7;
}

arr[0][1][0] is 7, so you get 7+2+7, which is 16.

Answer 2

**(*arr + 1) + 2 + 7

Is the same as

**(arr[0] + 1) + 2 + 7

Same as

arr[0][1][0] + 2 + 7

arr[0][1][0] Is 7 by definition.

So the compiler is correct and answer is 16.

Answer 3

The other answers are correct. Try doing this in your code to see it in action for yourself:

#include <iostream>
int main()
{
    int arr[2][3][2]=
      {
        {
          {2,4},{7,8},{3,4},
        },
        {
          {2,2},{2,3},{3,4},
        }
      };
    std::cout << *arr << std::endl;            // 0x7fff5a3a6710
    std::cout << *arr+1 << std::endl;          // 0x7fff5a3a6718
    std::cout << *(*arr+1) << std::endl;       // 0x7fff5a3a6718
    std::cout << **(*arr+1) << std::endl;      // 7
    std::cout << **(*arr+1)+2+7 << std::endl;  // 16

    return 0;
}