we & with 15 to get hexadecimal

Author: Arjiit

bit_manipulation/toHex.java

@@ -0,0 +1,29 @@
+class Solution {
+    public String toHex(int num) {
+        /*
+        int has 32 bits, and we check 4 bits at a time, so we will loop 8 times.
+        */
+        if (num ==0) {
+            return "" + "0";
+        }
+        
+        String map = "0123456789abcdef";
+        String res = "";
+        for (int i=0; i<8; i++) {
+            int ans = num&15; // 15 is 1111b , so we get hexadecimal by &
+            char c = map.charAt(ans);
+            res = c + res; // add our result
+            num = num >> 4; // right shift by 4, to check the next 4
+        }
+        String ret = "";
+        for (int i=0; i<res.length(); i++) { // we strip off any leading 0's.
+            if (res.charAt(i) == '0') {
+                continue;
+            } else {
+                ret = res.substring(i, res.length());
+                break;
+            }
+        }
+        return ret;
+    }
+}