LeetCode--Excel Sheet Column Number

题目:

Related to question Excel Sheet Column Title

Given a column title as appear in an Excel sheet, return its corresponding column number.

For example:

    A -> 1    B -> 2    C -> 3    ...    Z -> 26    AA -> 27    AB -> 28 

代码:

    int titleToNumber(string s) {        int n = 0;        int c = s.length()-1;        for(int i = 0; i < s.length(); ++i)        {            n += (((int)s[i])-64)*pow(26.0, c--);        }        return n;    }