package Question5_1;

import CtCILibrary.AssortedMethods;

public class Question {

public static int updateBits(int n, int m, int i, int j) {

// Validation

if (i >= 32 || j < i) {

return 0;

}

/* Create a mask to clear bits i through j in n

/* EXAMPLE: i = 2, j = 4. Result should be 11100011.

* (Using 8 bits for this example. This is obviously not actually 8 bits.)

*/

int allOnes = ~0; // allOnes = 11111111

int left = allOnes << (j + 1); // 1s through position j, then 0s. left = 11100000

int right = ((1 << i) - 1); // 1’s after position i. right = 00000011

int mask = left | right; // All 1s, except for 0s between i and j. mask = 11100011

/* Clear i through j, then put m in there */

int n_cleared = n & mask; // Clear bits j through i.

int m_shifted = m << i; // Move m into correct position.

/* OR them, and we're done! */

return n_cleared | m_shifted;

}

public static void main(String[] args) {

int a = 103217;

System.out.println(AssortedMethods.toFullBinaryString(a));

int b = 13;

System.out.println(AssortedMethods.toFullBinaryString(b));

int c = updateBits(a, b, 4, 12);

System.out.println(AssortedMethods.toFullBinaryString(c));

}

}