str="dotnetfunda"
# Method 1:
char[] strChar= str.ToCharArray();
Array.Reverse(strChar);
return new string(strChar);
# Method 2:
string revString = string.Empty;
for (int i = str.Length - 1; i >= 0; i--)
{
revString += str[i'];
}
Please remove the single quote from the str[i']