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;
    }