| 1 | public class BitOperations { |
| 2 | //Get ith Bit |
| 3 | public static int getIthBit(int n, int i) { |
| 4 | int bitMask = 1<<i; |
| 5 | return (n & bitMask) == 0 ? 0 : 1; |
| 6 | } |
| 7 | |
| 8 | //Set ith Bit |
| 9 | public static int setIthBit(int n, int i) { |
| 10 | int bitMask = 1<<i; |
| 11 | return n | bitMask; |
| 12 | } |
| 13 | |
| 14 | //Clear ith Bit |
| 15 | public static int clearIthBit(int n, int i) { |
| 16 | int bitMask = ~(1<<i); |
| 17 | return n & bitMask; |
| 18 | } |
| 19 | |
| 20 | //Update ith Bit |
| 21 | public static int updateIthBit(int n, int i, int val) { |
| 22 | //Method1 |
| 23 | // if(val == 0) { |
| 24 | // return n & (~(1<<i)); |
| 25 | // } else { |
| 26 | // return n | (1<<i); |
| 27 | // } |
| 28 | |
| 29 | //Method2 |
| 30 | n = clearIthBit(n, i); |
| 31 | int bitMask = val<<i; |
| 32 | return n | bitMask; |
| 33 | } |
| 34 | |
| 35 | //Clear Last i Bits |
| 36 | public static int clearLastIbits(int n, int i) { |
| 37 | int bitMask = (~0)<<i; // or (-1)<<i |
| 38 | return n | bitMask; |
| 39 | } |
| 40 | |
| 41 | //Clear Bits in Range (i,j) |
| 42 | public static int clearBitsinRange(int n, int i, int j) { |
| 43 | int a = ~0<<i; |
| 44 | int b = (1<<i)-1; |
| 45 | int bitMask = a | b; |
| 46 | return n & bitMask; |
| 47 | } |
| 48 | |
| 49 | //Check if number is power of 2 or not |
| 50 | public static boolean isPowerof2(int n) { |
| 51 | return (n & (n-1)) == 0; |
| 52 | } |
| 53 | |
| 54 | //Count number of set bits |
| 55 | public static int countSetBits(int n) { |
| 56 | int setBits = 0; |
| 57 | int bitMask = 1; |
| 58 | while(n != 0) { |
| 59 | if((n & bitMask) != 0) { //last bit is 1 |
| 60 | setBits++; |
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