## Algorithm

Problem Name: 504. Base 7

Given an integer `num`, return a string of its base 7 representation.

Example 1:

```Input: num = 100
Output: "202"
```

Example 2:

```Input: num = -7
Output: "-10"
```

Constraints:

• `-107 <= num <= 107`

## Code Examples

### #1 Code Example with Java Programming

```Code - Java Programming```

``````
class Solution {
public String convertToBase7(int num) {
StringBuilder sb = new StringBuilder();
char sign = num < 0 ? '-' : ' ';
num = Math.abs(num);
while (num > 0) {
sb.append(num % 7);
num /= 7;
}
String representation = sb.length() == 0 ? "0" : sb.reverse().toString();
if (sign == '-') {
return sign + representation;
}
return representation;
}
}
``````
Copy The Code &

Input

cmd
num = 100

Output

cmd
"202"

### #2 Code Example with Javascript Programming

```Code - Javascript Programming```

``````
const convertToBase7 = function(num) {
if(num == null) return ''
const sign = num >= 0 ? '+' : '-'
let res = ''
let remain = Math.abs(num)
if(num === 0) return '0'
while(remain > 0) {
res = remain % 7 + res
remain = Math.floor(remain / 7)
}

return sign === '+' ? res : '-' + res
};
``````
Copy The Code &

Input

cmd
num = 100

Output

cmd
"202"

### #3 Code Example with Python Programming

```Code - Python Programming```

``````
class Solution:
def convertToBase7(self, num):
lead = "" if num > 0 else "0" if num == 0 else "-"
res, num = [], abs(num)
while num:
res.append(int(num % 7))
num //= 7
return lead + "".join(str(c) for c in res[::-1])
``````
Copy The Code &

Input

cmd
num = -7

Output

cmd
"-10"

### #4 Code Example with C# Programming

```Code - C# Programming```

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

namespace LeetCode
{
public class _0504_Base7
{
public string ConvertToBase7(int num)
{
if (num == 0) return "0";

var signal = num < 0;
if (num < 0) num = -num;

var sb = new StringBuilder();
while (num > 0)
{
sb.Append((num % 7).ToString());
num /= 7;
}
if (signal)
sb.Append('-');

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

Input

cmd
num = -7

Output

cmd
"-10"