2 D array pointer

#1

https://ide.codingblocks.com/#/s/12662
in this b is a row pointer to array a.
but i am able to change value of a[i][j] by b[i][j]=2 how
if b is a pointer i should change value of a by *b[i][j]=

#2

Compiler converts b[i][j] into ((b+i) + j). The first star automatically means de-referencing.
Similarly *(a+i) means a[i] for linear array.
(a+i) gives the address.
*(a+i) gives the value of the cell.