Programming Riddle: How might you translate an Excel column name to a number?

Question

I was recently asked in a job interview to resolve a programming puzzle that I thought it would be interesting to share. It\'s about translating Excel column letters to actu

Answer 1

Assuming column A = 1

int GetColumnNumber(string columnName)
{
  int sum = 0;
  int exponent = 0;
  for(int i = columnName.Length - 1; i>=0; i--)
  {
    sum += (columnName[i] - 'A' + 1) *  (GetPower(26, exponent));
    exponent++;
  }
  return sum;
}

int GetPower(int number, int exponent)
{
  int power = 1;
  for(int i=0; i