Merge pull request TheAlgorithms#694 from arodriguez33/Development

yanglbme · web-flow · commit fe277cf053a0 · 2019-01-30T17:09:13.000+08:00
conversion binary to hexadecimal
diff --git a/src/main/java/com/conversions/BinaryToHexadecimal.java b/src/main/java/com/conversions/BinaryToHexadecimal.java
@@ -0,0 +1,52 @@
+package src.main.java.com.conversions;
+
+import java.math.BigInteger;
+import java.util.HashMap;
+import java.util.Map;
+
+
+public class BinaryToHexadecimal {
+
+    /**
+     * hm to store hexadecimal codes for binary numbers
+     * within the range: 0000 to 1111 i.e. for decimal numbers 0 to 15
+     */
+   private static Map<Integer, String> hmHexadecimal = new HashMap<>(16);
+
+    static {
+        int i;
+        for (i = 0; i < 10; i++)
+            hmHexadecimal.put(i, String.valueOf(i));
+
+        for (i = 10; i < 16; i++)
+            hmHexadecimal.put(i, String.valueOf((char) ('A' + i - 10)));
+    }
+
+    /**
+     * This method converts a binary number to
+     * a hexadecimal number.
+     *
+     * @param binStr The binary number
+     * @return The hexadecimal number
+     */
+
+    public String binToHex(String binStr) {
+        BigInteger binary = new BigInteger(binStr);
+        // String to store hexadecimal code
+        String hex = "";
+
+        int currentBit;
+        BigInteger tenValue = new BigInteger("10");
+        while (binary.compareTo(BigInteger.ZERO) != 0) {
+            // to store decimal equivalent of number formed by 4 decimal digits
+            int code4 = 0;
+            for (int i = 0; i < 4; i++) {
+                currentBit = binary.mod(tenValue).intValueExact();
+                binary = binary.divide(tenValue);
+                code4 += currentBit * Math.pow(2, i);
+            }
+            hex = hmHexadecimal.get(code4) + hex;
+        }
+        return hex;
+    }
+}
diff --git a/src/test/java/com/conversions/BinaryToHexadecimalTest.java b/src/test/java/com/conversions/BinaryToHexadecimalTest.java
@@ -0,0 +1,16 @@
+package src.test.java.com.conversions;
+
+import org.junit.Test;
+import src.main.java.com.conversions.BinaryToHexadecimal;
+import org.junit.Assert;
+
+public class BinaryToHexadecimalTest {
+
+    @Test
+    public void testBinaryToHexadecimal(){
+        BinaryToHexadecimal binaryToHexadecimal = new BinaryToHexadecimal();
+        Assert.assertEquals("Incorrect Conversion", "2A", binaryToHexadecimal.binToHex("101010"));
+        Assert.assertEquals("Incorrect Conversion", "24", binaryToHexadecimal.binToHex("100100"));
+        Assert.assertEquals("Incorrect Conversion", "AAAAAAAAAAAAAAAAAA1", binaryToHexadecimal.binToHex("1010101010101010101010101010101010101010101010101010101010101010101010100001"));
+    }
+}
