实现strstr函数 C#

C# as below:

 

public static int StrStr(string str1, string str2)

        {

            int result = -1;

            int i = 0;

            int j = 0;

 

            while (i <= str1.Length - str2.Length)

            {

                if (str1[i] == str2[j])

                {

                    if (j == str2.Length - 1)

                    {

                        result = i - j;

                        break;

                    }

                    else

                    {

                        j++;

                    }

                }

                else

                {

                    i -= j;

                    j = 0;

                }

                i++;

            }

 

            return result;

        }