Engaged Employer
LinkedIn Interview Question
Write a function to determine if a string is a number without using any built-in function.
Interview Answers
Anonymous
Here is my 15 mins C# solution after the interview: public bool IsNumber(string number) { int n = number.Length, dots = 0; if (number[0] == '.' || number[n - 1] == '.' || number[n - 1] == '-') return false; if ((number[0] 57) && number[0] != '-') return false; for (var i = 1; i 1) return false; if (number[i] 57) { if (number[i] == '.') { if (i == 1 && number[0] == '-') return false; else dots++; } else return false; } } return true; }