public class BitArray { private int[] bitArray; private int size; public void init(int size) { int arraySize = size / 32; if (size % 32 > 0) arraySize++; bitArray = new int [arraySize]; this.size = size; print(); } public void set(int i, int val) { if (val != 1 && val != 0) { System.out.println("val should be 1 or 0"); return; } if (i < 0 || i >= size) { System.out.println("i should be in the range [0, " + (size - 1) + "]"); } int arrayIndex = i / 32; int bitIndex = i % 32; System.out.println("array index: " + arrayIndex + ", bit index: " + bitIndex); setBit(arrayIndex, bitIndex, val); } public int get(int i) { if (i < 0 || i >= size) { System.out.println("i should be in the range [0, " + (size - 1) + "]"); } int arrayIndex = i / 32; int bitIndex = i % 32; System.out.println("array index: " + arrayIndex + ", bit index: " + bitIndex); return getBit(arrayIndex, bitIndex); } void setBit(int arrayIndex, int bitIndex, int val) { int mask = -1; int bit = 1 << bitIndex; mask ^= bit; bitArray[arrayIndex] = bitArray[arrayIndex] & mask; val <<= bitIndex; bitArray[arrayIndex] = bitArray[arrayIndex] | val; print(); } int getBit(int arrayIndex, int bitIndex) { int mask = 1 << bitIndex; return (bitArray[arrayIndex] & mask) >> bitIndex; } public void print() { for (int i = 0; i < bitArray.length; i++) System.out.print(bitArray[i] + " "); System.out.println(); } public void printAsBinary() { StringBuilder sb = new StringBuilder(); int val = 0; int count = 0; for (int i = 0; i < bitArray.length; i++) { val = bitArray[i]; count = 32; while (count > 0) { sb.append("" + (val & 1)); val >>= 1; count--; } sb.append(" "); } System.out.println(sb.toString()); } public static void main(String[] args) { BitArray ba = new BitArray(); int size = 1200; int i = 37; int val = 1; ba.init(size); ba.set(i, val); i = 37; ba.set(i, val); i = 67; ba.set(i, val); i = 7; ba.set(i, val); i = 107; ba.set(i, val); System.out.println(ba.get(i)); ba.printAsBinary(); } }