Leetcode- hex number - simple

title ：504 Octal number - Simple

subject

Given an integer num, Convert it to 7 Base number , And output... As a string .

Example 1

 Input : num = 100
 Output : "202"

Example 2

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

Tips

• -107 <= num <= 107

Code Java

		public String convertToBase7(int num) {
    
        StringBuilder sb = new StringBuilder();
        int flag = 0;
        if (num == 0)
            return sb.append(0).toString();
        else if (num < 0) {
    
            flag = 1;
            num = -num;
        }
        while (num != 0) {
    
            sb.append(num % 7);
            num /= 7;
        }
        if (flag == 1)
            sb.append('-');
        return sb.reverse().toString();
    }