String_To_Integer.py

"""
@author - Anirudh Sharma
"""


def myAtoi(s: str) -> int:
 # Base condition
 if s is None or len(s) < 1:
 return 0
 # Max and Min values for the integers
 INT_MAX = 2147483647
 INT_MIN = -2147483648
 # Trimmed string
 s = s.lstrip()
 # Counter
 i = 0
 # Flag to indicate if the number is negative
 isNegative = len(s) > 1 and s[0] == '-'
 # Flag to indicate if the number is positive
 isPositive = len(s) > 1 and s[0] == '+'
 if isNegative:
 i += 1
 elif isPositive:
 i += 1
 # This will store the converted number
 number = 0
 # Loop for each numeric character in the string iff numeric characters are leading
 # characters in the string
 while i < len(s) and '0' <= s[i] <= '9':
 number = number * 10 + (ord(s[i]) - ord('0'))
 i += 1
 # Give back the sign to the number
 if isNegative:
 number = -number
 # Edge cases - integer overflow and underflow
 if number < INT_MIN:
 return INT_MIN
 if number > INT_MAX:
 return INT_MAX
 return number


if __name__ == '__main__':
 print(myAtoi("42"))
 print(myAtoi(" -42"))
 print(myAtoi("4193 with words"))
 print(myAtoi("words and 987"))
 print(myAtoi("-91283472332"))
 print(myAtoi("91283472332"))
 print(myAtoi("9223372036854775808"))
 print(myAtoi(" "))