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].
class Solution { //水题
public:
string convertToBase7(int num) {
string ans;
int flag=0;
if(num<0)
flag=1;
else if(num==0)
ans.insert(ans.begin(),1,'0');
num=abs(num);
while(num){
ans.insert(ans.begin(),1,'0'+num%7);
num/=7;
}
if(flag)
ans.insert(ans.begin(),1,'-');
return ans;
}
};