public class ZeroBitsEveryStep {
/**
zeroBitsEveryStep(number, step)
-------------------------------
Zeros every `step`-th bit (0-based from LSB)
but only if that bit is currently 1.
Example:
number = 536870911
step = 3 → zero bits 0, 3, 6, 9, ...
*/
public static int zeroBitsEveryStep(int number, int step) {
int result = number;
for (int pos = 0; pos < 32; pos += step) {
int mask = 1 << pos;
// If the bit is 1, zero it
if ((result & mask) != 0) {
result &= ~mask;
}
}
return result;
}
/**
printBinary(n)
--------------
Prints a 32-bit binary representation of an integer.
*/
public static void printBinary(int n) {
String s = String.format("%32s", Integer.toBinaryString(n))
.replace(' ', '0');
for (int i = 0; i < 32; i++) {
System.out.print(s.charAt(i));
if ((i + 1) % 4 == 0) System.out.print(" ");
}
}
public static void main(String[] args) {
int number = 536870911; // 0001 1111 1111 1111 1111 1111 1111 1111
int step = 3; // zero bits 0, 3, 6, 9, ...
System.out.println("Original number in binary:");
printBinary(number);
int result = zeroBitsEveryStep(number, step);
System.out.println("\n\nNumber after zeroing every " + step +
" bits (only if bit was 1):");
printBinary(result);
System.out.println("\n\nResult as integer: " + result);
}
}
/*
run:
Original number in binary:
0001 1111 1111 1111 1111 1111 1111 1111
Number after zeroing every 3 bits (only if bit was 1):
0001 0110 1101 1011 0110 1101 1011 0110
Result as integer: 383479222
*/
