Doubt in 2d-array

#1

Please refer the image below.
Why we make array like this and how it’s different from int solution[n] [n] ?

Please help me out. Thanks in advance.

#2

Hey @gambhirrahul0 int **arr = new int [n] is a way to declare 2 D array dynamically. As arr[n][n] is static allocation whereas int **arr = new int [n] is dynamic allocation.

image
image1822×1142 173 KB

Here arr[i] is a pointer pointing to array of n indexes .

#3

Thanks! Will you please explain the working of those 4 lines in more detail?

#4

So what it does is, in the first line you are declaring n pointers name arr . See it like this
int *(*arr) = new int [n]
Just think *arr as p so you will get the intuition of dynamically declaring a 1d array . Since your p is a pointer and you have n pointers .
You run a for loop and declare p[i] = new int [n] which looks like
int arr[i] = new int [n] now this is 1d dynamic allocation.
If you have any more doubts left regarding this then do let me know.

#5

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