[LeetCode] 504. Base 7 ❤

Given an integer, return its base 7 string representation.

Example 1:

Input: 100
Output: "202"

Example 2:

Input: -7
Output: "-10"

Note: The input will be in range of [-1e7, 1e7].

_____________________________________________ 以上题目

十进制转n进制的题目，思路相同。加了一个判断正负，加了一个reverse字符串。完成

class Solution {
public:
string convertToBase7(int num) {
string ret;
int shang, yushu;
shang = abs(num) / 7;
yushu = abs(num) % 7;
while (shang != 0) {
ret += yushu + '0';
yushu = shang % 7;
shang /= 7;
}
ret += yushu + '0';
reverse(ret.begin(), ret.end());
if (num < 0) ret.insert(ret.begin(), '-');
return ret;
}
};