String to Interger

Steilla Mitchel 918 11 Jun 2024

Implement the myAtoi(string s) function, which converts a string to a 32-bit signed integer.

The algorithm for myAtoi(string s) is as follows:

Whitespace: Ignore any leading whitespace (" ").
Signedness: Determine the sign by checking if the next character is '-' or '+', assuming positivity is neither present.
Conversion: Read the integer by skipping leading zeros until a non-digit character is encountered or the end of the string is reached. If no digits were read, then the result is 0.
Rounding: If the integer is out of the 32-bit signed integer range [-2³¹, 2³¹ - 1], then round the integer to remain in the range. Specifically, integers less than -2³¹ should be rounded to -2³¹, and integers greater than 2³¹ - 1 should be rounded to 2³¹ - 1.

Return the integer as the final result.

Ask by Steilla Mitchel

Updated 12 Jun 2024

1 Answers

Ravi Vishwakarma 12 Jun 2024

Let's write code for String to Integer in C#. Create MyAtoi function to convert string to integer.

        /// <summary>
        /// This function return an integer after converting a string
        /// </summary>
        /// <param name="s"></param>
        /// <returns>return an integer, after converting to a string.</returns>
        public static int MyAtoi(string s)
        {
            //check string is is null or empty 
            if (string.IsNullOrEmpty(s))
            {
                return 0;
            }

            int i = 0, sign = 1, result = 0, n = s.Length;
            
            // Discard leading whitespaces
            while (i < n && s[i] == ' ')
            {
                i++;
            }

            // Check for optional sign
            if (i < n && (s[i] == '+' || s[i] == '-'))
            {
                sign = (s[i] == '-') ? -1 : 1;
                i++;
            }

            // Convert characters to digits and handle overflow/underflow
            while (i < n && s[i] >= '0' && s[i] <= '9')
            {
                int digit = s[i] - '0';

                // Check for overflow and underflow
                if (result > (int.MaxValue - digit) / 10)
                {
                    return (sign == 1) ? int.MaxValue : int.MinValue;
                }

                result = result * 10 + digit;
                i++;
            }

            return result * sign;
        }

Now call this function through main().

using System;

namespace ConsoleApp1
{
    public class Program
    {
        public static void Main()
        {
            string[] array = { "42", " -042", "13-37c0d3", "0-1", "words and 987" };
            foreach (var item in array)
            {
                Console.WriteLine(Program.MyAtoi(item));
            }
        }



    }
}

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String to Interger

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