Question

We decide to rewrite our code to be more cache-efficient, while maintaining the same behavior. Fill in the blanks of this code (write your answers in the same format as the original code):

int i, j, array256*256;
/* ... */
for (code a; i < 256 ; i )
for (code b; j < 256 ; j )
arraycode c


a) code a: i = 0
b) code b: j = 0
c) code c: i * 256 + j
d) code c: i * 256 + i + j

Answer 1

The code can be rewritten using two loops to iterate over 'i' and 'j' from 0 to 255. The equation 'i * 256 + j' is used to calculate the index in the array, and the calculated value is stored in the corresponding position.

Step-by-step explanation:

The code can be rewritten as follows:

int i, j, array[256][256];
for (i = 0; i < 256 ; i++) {
for (j = 0; j < 256 ; j++) {
array[i][j] = (i * 256) + j;
}
}

In the modified code, two loops are used. The outer loop iterates over the variable 'i' from 0 to 255, and the inner loop iterates over the variable 'j' from 0 to 255. In each iteration, the value of 'i' and 'j' are used to calculate the index in the array using the equation 'i * 256 + j'. The calculated value is then stored in the corresponding position in the array.