Leetcode #171 Excel Sheet Column Number

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 

int titleToNumber(char* s) {    int len = strlen(s);int i;int sum = 0;for (i = 0; i < len; ++i){if (s[i] >= 'A' && s[i] <= 'Z')sum = sum * 26 + (s[i] - 'A' + 1);}return sum;}