Bitwise and Bit Shift

Java Bitwise and Bit Shift Operators

Operator Description
| Bitwise OR
& Bitwise AND
~ Bitwise Complement
^ Bitwise XOR
<< Left Shift
>> Right Shift
>>> Unsigned Right Shift

example

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System.out.printf("%d*%d=%d", 2,8,2<<3);

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System.out.printf("%d/2=%d",11,11>>1);

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public static boolean isOddNum(int n) {
    return (n & 1)==1;
}

4

public static int powerofTwo(int n) {
    return 2<<(n-1);
}

5

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/**
 * how to multiply two arbitrary integers a and b (a greater than b) 
 * using only bitshifts and addition
 * @param a
 * @param b
 * @return
 */
public static int multiply(int a, int b) {
	int c = 0;
	while (b!=0) {
		if ((b & 1)!=0)
			c+=a;
		a <<= 1;
		b >>= 1;
	}
	return c;
}

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/**
 * how to calculate a sum of two integers a and b 
 * using bitwise operators and zero-testing
 * @param a
 * @param b
 * @return
 */
public static int sum(int a, int b) {
	int c=0;
	while(a!=0) {
		c = b & a;
		b = b ^ a;
		c <<= 1;
		a = c;
	}
	return b;
}

JavaScript Bitwise Operators

Operator Name Description
& AND Sets each bit to 1 if both bits are 1
&#124; OR Sets each bit to 1 if one of two bits is 1
^ XOR Sets each bit to 1 if only one of two bits is 1
~ NOT Inverts all the bits
<< Zero fill left shift Shifts left by pushing zeros in from the right and let the leftmost bits fall off
>> Signed right shift Shifts right by pushing copies of the leftmost bit in from the left, and let the rightmost bits fall off
>>> Zero fill right shift Shifts right by pushing zeros in from the left, and let the rightmost bits fall off

ref