## Algorithm

Problem Name: 405. Convert a Number to Hexadecimal

Given an integer `num`, return a string representing its hexadecimal representation. For negative integers, two’s complement method is used.

All the letters in the answer string should be lowercase characters, and there should not be any leading zeros in the answer except for the zero itself.

Note: You are not allowed to use any built-in library method to directly solve this problem.

Example 1:

```Input: num = 26
Output: "1a"
```

Example 2:

```Input: num = -1
Output: "ffffffff"
```

Constraints:

• `-231 <= num <= 231 - 1`

## Code Examples

### #1 Code Example with Java Programming

```Code - Java Programming```

``````
class Solution {
char[] map = {'0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f'};

public String toHex(int num) {
if(num == 0) return "0";
String result = "";
while(num != 0){
result = map[(num & 15)] + result;
num = (num >>> 4);
}
return result;
}
}
``````
Copy The Code &

Input

cmd
num = 26

Output

cmd
"1a"

### #2 Code Example with Javascript Programming

```Code - Javascript Programming```

``````
const toHex = function(num) {
const bin = (num >>> 0).toString(2)
const arr = ['0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f']
const mod = bin.length % 4
const r = []
if(mod !== 0 ){
r.push(arr[ parseInt(bin.slice(0, mod),2) ])
}

for(let i = mod; i < bin.length; i = i + 4) {
r.push(arr[ parseInt(bin.slice(i, i+4),2) ])
}
return r.join(''>
};
``````
Copy The Code &

Input

cmd
num = 26

Output

cmd
"1a"

### #3 Code Example with Python Programming

```Code - Python Programming```

``````
class Solution:
def toHex(self, num):
if not num: return "0"
mp, ans = "0123456789abcdef", ""
for i in range(8):
n = num & 15
c = mp[n]
ans = c + ans
num = num >> 4
return ans.lstrip('0')
``````
Copy The Code &

Input

cmd
num = -1

Output

cmd
"ffffffff"

### #4 Code Example with C# Programming

```Code - C# Programming```

``````
using System.Linq;
using System.Text;

namespace LeetCode
{
public class _0405_ConvertANumberToHexadecimal
{
public string ToHex(int num)
{
if (num == 0) return "0";

var map = "0123456789abcdef";
var sb = new StringBuilder();
while (num != 0 && sb.Length  <  8)
{
sb.Append(map[num & 15]);
num >>= 4;
}

return new string(sb.ToString().ToCharArray().Reverse().ToArray());
}
}
}
``````
Copy The Code &

Input

cmd
num = -1

Output

cmd
"ffffffff"
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