Question

In C language, mat[i][j] is equivalent to: (where mat[i][j] is a two-dimensional array)

• A. \(\texttt{*(mat + i) + j}\)
• B. \(\texttt{(mat + i) + j}\)
• C. \(\texttt{((mat * i) + j)}\)
• D. \(\texttt{*(mat + i + j)}\)

Hint:

In C, accessing a two-dimensional array element using pointer arithmetic is done by calculating the base address and adding the appropriate offsets.

Answer 1

The Correct Option is A

 

Step 1: Understand how multi-dimensional arrays work in C. 
In C, a 2D array is stored in a contiguous block of memory. To access an element at \( mat[i][j] \), you use a pointer arithmetic approach. 

- **Option 1**: \(\texttt{*(mat + i) + j}\) is the correct way to access the element at \(mat[i][j]\), because it first calculates the address of the \(i^{th}\) row and then accesses the \(j^{th}\) column element.

Step 2: Evaluate other options. 

- **Option 2**: This is not valid because \( (mat + i) + j \) is not a proper way to access the array element. 

- **Option 3**: Incorrect, as this formulation tries to use multiplication on the array, which is not valid for accessing a specific element. 

- **Option 4**: Incorrect. The formula \( *(mat + i + j) \) does not correctly access the element at row \(i\) and column \(j\).

Step 3: Conclusion. 
Thus, the correct expression is **Option 1**.