Exams › GATE › Technical

For a C program accessing X[i][j][k], the following intermediate code is generated by a compiler. Assume that the size of an integer is 32 bits and the size of a character is 8 bits. t0 = i * 1024 t1 = j * 32 t2 = k * 4 t3 = t1 + t0 t4 = t3 + t2 t5 = X[t4] Which one of the following statements about the source code for the C program is correct?

1. X is declared as "int X[32][32][8]".
2. X is declared as "int X[4][1024][32]".
3. X is declared as "char X[4][32][8]".
4. X is declared as "char X[32][16][2]".

Correct answer: X is declared as "int X[32][32][8]".

Solution

In row-major order, the offset for X[i][j][k] in a 3D array int X[a][b][c] is ((i·b + j)·c + k)·4 bytes. The given code computes i·1024 + j·32 + k·4, which matches ((i·32 + j)·8 + k)·4. Hence the declaration is int X[32][32][8].

Related GATE Technical questions

• The three-dimensional state of stress at a point is given by $\sigma = \begin{bmatrix}10 & 0 & 0\\0 & 40 & 0\\0 & 0 & 0\end{bmatrix}$ MPa. The maximum shear stress at the point is
• Consider the statements P and Q. P: Client’s preliminary estimate is used for budgeting costs toward the end of the planning and design phase. Q: Client’s detailed estimate is used for controlling costs during the execution of the project. Which one of the following options is correct?
• The following figure shows the arrangement of formwork for casting a cantilever RC beam. The correct sequence of removing the shores/props is
• A 2 m wide strip footing is founded at a depth of 1.5 m below ground level in a homogeneous pure clay bed. The clay bed has unit cohesion of 40 kPa. Due to seasonal fluctuations of the water table from peak summer to peak monsoon period, the net ultimate bearing capacity of the footing, as per Terzaghi’s theory, will
• Consider the statements P and Q. P: Soil particles formed by mechanical weathering and close to their origin are generally subrounded. Q: The activity of clay physically signifies its swell potential. Which one of the following options is correct?
• The number of degrees of freedom for a natural open channel flow with a mobile bed is

⚔️ Practice GATE Technical free + battle 1v1 →