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Optimize the Algotithm

So, i have a method
public void AddToSearch(List<FullName> fullNames)
{
foreach (var fullName in fullNames)
{
if (fullName.Surname != null)
_sb.Append(fullName.Surname.Trim() + " ");
if (fullName.Name != null)
_sb.Append(fullName.Name.Trim() + " ");
if (fullName.Patronymic != null)
_sb.Append(fullName.Patronymic.Trim());
fullNamesList.Add(_sb.ToString().TrimEnd());
_sb.Clear();
}
it takes a list of FullName and by using StringBuilder instance converts each element into a string(which format is "$Surname $Name $Patronymic"). At the end i put the result into my list. The Question is - how can i optimize all of that "Trim" stuff. It bothers me that i use it in multiple occassions and i am pretty sure it effects the time.

how can i optimize all of that "Trim" stuff
Very simple, simply don't call Trim() on those strings. What spaces are you worried about? Who's entering those values in your business objects? Because short of solar flares randomly flipping bits enough to append spaces to your strings, you're in full control from beginning to end, so simply don't add the spaces.
You also don't need the two string builders, just insert in your main one. There's no need for yet another Trim() here either, because simply decrementing the Length property of your string builder is a constant operation (it literally decrements one integer with guaranteed no extra allocations).

the strings normalization process should be done in the data layer (in application or database) for stored strings. While dynamic strings such as user input, needs to be normalized as soon as you get them to prepare them for the next task.
For your current code, you can modify the FullName class, adjust the setters to trim the value before it's been stored, and override the ToString to return the full name.
Example :
public class FullName
{
public string Name
{
get => Name;
set => Name = value?.Trim();
}
public string Surname
{
get => Surname;
set => Surname = value?.Trim();
}
public string Patronymic
{
get => Patronymic;
set => Patronymic = value?.Trim();
}
public override string ToString()
{
return $"{GetValueOrEmpty(Surname)}{GetValueOrEmpty(Name)}{GetValueOrEmpty(Patronymic, false)}";
}
private string GetValueOrEmpty(string name, bool addSpaceAfter = true)
{
if(!string.IsNullOrWhiteSpace(name))
{
return name + (addSpaceAfter ? " " : string.Empty);
}
return string.Empty;
}
}
Then, you can do this :
fullNamesList.AddRange(fullNames.Select(x=> x.ToString()));
UPDATE :
Thanks to #olivier-jacot-descombes, the above code is missing the use of backing fields, which will avoid causing overflow exception by the properties infinite recursions. The following adjustments will do the trick.
public class FullName
{
private string _name;
private string _surname;
private string _patronymic;
public string Name
{
get => _name;
set => _name = value?.Trim();
}
public string Surname
{
get => _surname;
set => _surname = value?.Trim();
}
public string Patronymic
{
get => _patronymic;
set => _patronymic = value?.Trim();
}
public override string ToString()
{
return $"{GetValueOrEmpty(Surname)}{GetValueOrEmpty(Name)}{GetValueOrEmpty(Patronymic, false)}";
}
private string GetValueOrEmpty(string name, bool addSpaceAfter = true)
{
if(!string.IsNullOrWhiteSpace(name))
{
return name + (addSpaceAfter ? " " : string.Empty);
}
return string.Empty;
}
}

Try and extension something like this.
public static class Helper
{
public static StringBuilder AppendValue(this StringBuilder builder,string value)
{
if(!string.IsNullOrEmpty(value))
{
builder.Append(value.Trim());
return builder;
}
}
}
call as follows:
sb.AppendValue(fullName.Name);
sb.AppendValue(fullName.Surname);
...
You will get the StringBuilder back with the value if it is not empty otherwise nothing will be added to it.

Convert object to string in C# [duplicate]

Okay, so I wrote this program from an exercise in a C# programming book (I'm trying to learn here) and it asks for "Override the ToString() method to return all data members".
Have I done this correctly? Or have I just successfully written code that compiles but does nothing? What is the purpose of ToString?
I have spent about 30 minutes looking at other posts on this and haven't figured it out, so I decided to make this.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication297
{
class Program
{
static void Main(string[] args)
{
String name = "Stormtrooper";
Employee s = new Employee(name);
Console.WriteLine("The type of hire is a {0}", s.Name);
Console.WriteLine("The identification number is {0}", s.Number);
Console.WriteLine("The date of hire is {0} ABY", s.Date);
Console.WriteLine("The standard galactic salary is...{0:C}", s.Salary);
}
class Employee
{
private string _name;
private string _number;
private int _date;
private int _salary;
public string Name
{
get
{
return _name;
}
}
public string Number
{
get
{
return _number;
}
}
public int Date
{
get
{
return _date;
}
}
public int Salary
{
get
{
return _salary;
}
}
public Employee(string n)
{
_name = n;
_number = "AA23TK421";
_date = 4;
_salary = 800;
}
}
public override string ToString()
{
return "_name + _number + _date + _salary".ToString();
}
}
}

You are returning a string that just says the phrase _name + _number + _date + _salary.
What you likely wanted to do is build a string using those fields. If you wanted them all mushed together Concat would work, but it would be highly un-readable
public override string ToString()
{
return String.Concat(_name, _number, _date, _salary);
}
However what would be better is to use Format and include labels with the values
public override string ToString()
{
return String.Format("Name:{0}, Number:{1}, Date:{2}, Salary:{3}",_name, _number, _date, _salary);
}
If you are using C# 6 or newer you can use the following cleaner format
public override string ToString()
{
return $"Name:{_name}, Number:{_number}, Date:{_date}, Salary:{_salary}";
}
Which is the exact same logic as the previous String.Format version.

The reason people override the ToString() method is to have a default string representation of your object, usually for display to the user or in a log or console, like this:
Console.WriteLine(yourClassObject);
If you do not override the ToString(), then its default implementation is to return the fully qualified name of your object, like this:
YourNamespace.YourClassName
By changing the inherited implementation (from System.Object), then you can make a nicer (read: prettier) representation, like this:
public override string ToString()
{
return String.Format("This instance of my object has the following: Name = {0}, Number = {1}, Date = {2}, Salary = ${3}", _name, _number, _date, _salary);
}

If you are using C# 6 (or later) use the nameof() method for the property names in the string in case the property names change. You can also use the $"" notation instead of using string.Format().
For example:
public override string ToString()
{
return $"{nameof(Name)}: {_name}";
}

Rather try something like
public override string ToString()
{
return String.Format("Name : {0}, number {1}, date {2}, salary {3}",_name,_number,_date,_salary);
}
But it neads to be part of the class
so
class Employee
{
private string _name;
private string _number;
private int _date;
private int _salary;
.....
public override string ToString()
{
return String.Format("Name : {0}, number {1}, date {2}, salary {3}",_name,_number,_date,_salary);
}
}
Have a look at String.Format Method
Replaces each format item in a specified string with the text
equivalent of a corresponding object's value.

You could try to format the output in a nice format. (not tested, though)
public override string ToString()
{
return string.Format("Name: {0} Number: {1:n0} Date: {2:yyyy-MM-dd} Salary: {3:n2}", _name, _number, _date, _salary);
}
there are a lot of purposes overwriting .ToString(), depending on the context. for example,
some developers like to have nicely formatted object description when doing debug, overwriting .ToString() would allow them to have meaningful description with some identifier (for example, the Id of a object);
Some developers like to put some serialization code into the ToString() method;
Some developers even put some debug code into the .ToString() method, though it might not be a good practice.
it really depending on the context of your needs. you may find some good practices to follow online - believe there are plenty of resources online.

Without overiding ToString, if you tried to "get" the string value of an Employee, e.g.
var employee1= new Employee();
Console.WriteLine(employee1);
What you'd get is:
ConsoleApplication1.Program+Employee
Which provides no information at all to help you (or a UI) display relevant information.
I use
return _name + _number + _date + _salary;
Which defaults to string,
or a more verbose
return "Name:" + _name + " Number:" + _number + " etc...";

class Program
{
static void Main( )
{
int Number = 10;
Console.WriteLine(Number.ToString());
Customer cc = new Customer();
cc.FirstName = "Rakibuz";
cc.LastName = "Sultan";
Console.WriteLine(Convert.ToString(cc));
}
}
public class Customer
{
public string FirstName;
public string LastName;
public override string ToString()
{
return FirstName + " " + LastName;
}
}

Why won't my objects print? [closed]

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Closed 8 years ago.
This question was caused by a typo or a problem that can no longer be reproduced. While similar questions may be on-topic here, this one was resolved in a way less likely to help future readers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Improve this question
New to the site as well as c#. This is my first time using c# and I can't get my objects to print properly. (example Million, Max 55. Cardenas, Jose, 22). I am pretty sure the error is in my accessors but I can't seem to get it right.
using System.IO;
using System;
class PersonApp
{
static void Main()
{
Random random = new Random();
Person p1 = new Person();
Person p2 = new Person();
p1.Fname = "Max";
p1.Lname = "Million";
p1.Id = random.Next(1,100);
p2.Fname = "Jose";
p2.Lname = "Cardenas";
p2.Id = random.Next(1,100);
Console.WriteLine(p1,p2);
}
}
using System.IO;
using System;
public class Person
{
private string Fname;
private string Lname;
private int Id;
public Person(){
Fname = string.empty;
Lname = string.empty;
Id = 0;
}
public string Fname
{
get
{
return Fname;
}
set
{
Fname = value;
}
}
public string Lname
{
get
{
return Lname;
}
set
{
Lname = value;
}
}
public int Id
{
get
{
return Id;
}
set
{
Id = value;
}
}
}

You have a few issues in your code.
First, you can't pass multiple values to Console.WriteLine like this:
Console.WriteLine(p1, p2);
Do one at a time:
Console.WriteLine(p1);
Console.WriteLine(p2);
Second, you can't name your private backing field and the public property used to get/set it the same. You can name them whatever you want... typically the private variable starts with a lower case or an underscore, but that's up to you.
Once you fix those, you'll still get unusual output, which is actually the full namespace of your class. That's the result of ToString() being implicitly called when you pass p1 to Console.WriteLine.
Override the ToString() method in your class:
public class Person
{
private string Fname;
private string Lname;
private int Id;
private override string ToString()
{
return string.Format("{0}, {1} {2}", Lname, Fname, Id);
}
...
...
}

You need to access property of the method to get the values printed
Wrong code :
Console.WriteLine(p1,p2); // You are trying to print Objects and this is wrong. !!
Correction : Use accessory's get to print the output.
Console.WriteLine(p1.Fname); // Print first name "Max"
Likewise
Console.WriteLine(p1.Lname); // print Last name
Console.WriteLine(p1.Id); // Print ID
Also your class need to be corrected
using System.IO;
using System;
public class Person{
private string fname;
private string lname;
private int id;
public string Fname
{
get
{
return fname;
}
set
{
fname = value;
}
}
public string Lname
{
get
{
return lname;
}
set
{
lname = value;
}
}
public int Id
{
get
{
return id;
}
set
{
id = value;
}
}
}
Now you can use it like
Person a = new Person();
a.Fname = "k";
a.Lname = "Do";
a.Id = 1024;
Console.WriteLine(a.Fname+" "+a.Lname+" "+a.Id);

You can't expect C# to know the format you want the object output in. You have to concatenate the strings yourself to produce the output.
The neatest way to do this is expose a readonly property on Person that formats it how you want, something like this:
public string DisplayName {
get {
return Lname + ", " + Fname + " " + Id;
}
}

How to string a value across two functions?

I am new to the world of c# so go easy on me! :]
I am not even sure I am using the correct terminology. I figured this would be an easy google search but I am afraid I may not be wording this correctly.
I am gathering data from a database. Like so:
SqlConnection mySqlConnection = new SqlConnection(strings.settings.connectionString);
SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
mySqlCommand.CommandText = "SELECT FNAME, LNAME, ZIPCODE FROM database WHERE ID = #ID";
mySqlCommand.Parameters.Add("#ID", SqlDbType.Char).Value = txtID.Text;
mySqlConnection.Open();
SqlDataReader mySqlDataReader = mySqlCommand.ExecuteReader(CommandBehavior.SingleRow);
if (mySqlDataReader.HasRows == false)
{
throw new Exception();
}
if (mySqlDataReader.Read())
{
txtFname.Text = mySqlDataReader[0].ToString();
txtLname.Text = mySqlDataReader[1].ToString();
lblZipcode.Text = mySqlDataReader[2].ToString();
//need help on stringing the value ZIPCODE above.
}
My question is: How can I string the Zipcode value to another function? I have been trying things like
string Zipcode = mySqlDataReader[2].ToString();
but I get stuck trying to figure out how to string that value so I can use it in a different function like so:
private void GetZipData()
{
//Get that value
}
Any help or a point in the right direction would be greatly appreciated!

Either I've misunderstood the question or your approach is fundamentally wrong. Firstly, your GetZipData() is returning void so is a subroutine, not a function. Even better, refer to it as a method as that covers both subs and funcs...
You can pass parameters in like this...
public void GetZipData(String SomeInputString) {
///Do something
}
and you can return things from a function like this...
public String GetZipData() {
return "Some String";
}
What I suspect you want to do is get either a single Zip code or a list of zip codes from a data reader. Something like...
public String GetZipData(Integer Id) {
//All your MySQL Code here
return mySqlDataReader[2].ToString();
}
then you can simply call it like this...
String TheZipCode = GetZipData(123);
Of course, there are other things you can consider doing too - like creating a class to represent a customer and return that instead of a string - then you can get all the information in one Db trip...
class Person {
String Firstname;
String Lastname;
String ZipCode;
}
public Person GetPersonData(Integer Id) {
//All your MySQL Code here
Person ReturnData = new Person();
ReturnData.Firstname = mySqlDataReader[0].ToString();
ReturnData.Lastname = mySqlDataReader[1].ToString();
ReturnData.ZipCode = mySqlDataReader[2].ToString();
return ReturnData;
}
Then you'd have...
Person person = GetPersonData(12);
//You can now use person.Firstname, person.ZipCode, etc...

Change this method as
private string GetZipData()
{
string Zipcode = mySqlDataReader[2] as String;
return Zipcode;
}

I am not sure what you are trying to achieve. If you want to pass the zip string to antoher method, you can add a string parameter to that method
private void DoSomethingWithZipCode(string zipCode)
{
Console.WriteLine(zipCode);
}
If you want to return antoher value that depends on the zip code, you need a return type as well
private string GetCity(string zipCode)
{
string city = <get city from database>;
return city;
}
Or in your case
private string GetZipData(SqlDataReader dataReader)
{
return dataReader[2].ToString();
}
You would call it like this
lblZipcode.Text = GetZipData(mySqlDataReader);
You can also write an extension method. You must place this method in a static class whose namespace is available where you are using it
public static string ZipData(this SqlDataReader dataReader)
{
return dataReader[2].ToString();
}
You can call it like this
lblZipcode.Text = mySqlDataReader.ZipData();

string Zipcode = mySqlDataReader[2].ToString();
private void GetZipData(string yourInput)
{
//do your stuff with yourInput
}

If your top data access code is in its own method you can 'return' it from there you would then call your data access method from the new value, see below:
return ZipCode
private void GetZipData() {
var stry=DataCode();
}
Regards
Craig

call methods from my class.cs

i was need to write 2 methods in my student class which do the following
hasPassed() Should return True if the student has a year mark >= 40 or
false if the marks is <40
toString() Should return a single string containing a summary of the
student details held within the class
e.g.
“12345 Basil Fawlty, 23/08/1946”
here's the code i have for the above to methods, is what i have correct for what its asking for the above?
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace CourseWork
{
public class Student
{
private static string firstname;
private string secondname;
private string dateofbirth;
private string course;
private int matricnumber;
private double yearmark;
public bool hasPassed()
{
if (yearmark >= 40)
return true;
else
return false;
}
public void toString()
{
firstname = "Basil";
secondname = "Fawlty";
dateofbirth = "23/08/1946";
course = "MA Hotel Management";
matricnumber = 12345;
yearmark = 55;
}
public Student()
{
}
public string FirstName
{
get { return firstname; }
set { firstname = value; }
}
public string SecondName
{
get { return secondname; }
set { secondname = value; }
}
public string DateOfBirth
{
get { return dateofbirth; }
set { dateofbirth = value; }
}
public string Course
{
get { return course; }
set { course = value; }
}
public int MatricNumber
{
get { return matricnumber; }
set
{
if (value <= 99999 && value >= 10000)
{
matricnumber = value;
}
else
{
Console.WriteLine("Invalid Matric Number: {0}", value);
}
matricnumber = value;
}
}
public double YearMark
{
set
{
if (value <= 100 && value >= 0)
{
yearmark = value;
}
else
{
Console.WriteLine("Invalid Year Mark: {0}", value);
}
yearmark = value;
}
}
}
i then need the above methods to be used in a get button that does the following
Get: Uses the values of the Student class methods to update the text boxes. The
Student.hasPassed() method should be used to update the pass/fail label. The
Student details summary should be updated by using Student.toString ().
but I'm having trouble coding it and i cant seam to call hasPassed() method or toString() method from my student class
so I've doing something wrong but cant see what it is
any ideas how to go about fixing this?
i have a set button that basically lets me save update vaules in the student class, though i dont think thats saving them correcty, but wont know until i get the Get button working i have used Student student = new student() in the set button in the get button i need to use the toString method to show the eg 12345 Basil Fawlty, 23/08/194 in the txt boxes and in a label, i then need to use hasPassed() method in the Get button so that when a yearmark is >= 40 another label says Pass or fail if < 40

I dont completely read your question because there are lots of errors.
For example
public void toString()
{
firstname = "Basil";
secondname = "Fawlty";
dateofbirth = "23/08/1946";
course = "MA Hotel Management";
matricnumber = 12345;
yearmark = 55;
}
where is your object?
you should create an object like this:
Student stu = new Student();
Be careful and ask your question more understandable!
Have a look :
https://stackoverflow.com/questions/902994/how-to-ask-programming-questions-correctly

The firstName variable is static. This will make all instances of Student share the same first name, which is not correct. Each Student object should have it's own first name.
The class's instance variables are private and have no way of being set. You probably want to create a constructor that takes these variables as arguments.
public Student(string firstName, string secondName, ...)
{
this.firstName = firstName;
this.secondName = secondName;
...
}
The hasPassed() method is correct. You can verify that the behavior is working by instantiating an instance of the Student class and calling hasPassed() on the instantiated object.
double goodYearMark = 85;
Student goodStudent = new Student("Basil", "Fawlty", ..., goodYearMark);
Console.WriteLine("Good Student Passed? " + goodStudent.hasPassed());
double badYearMark = 35;
Student badStudent = new Student("Bad", "Student", ..., badYearMark);
Console.WriteLine("Bad Student Passed? " + badStudent.hasPassed());
The ToString() method should return a string value. Every object in .NET has a ToString() method, and you can override the default behavior using the override keyword.
See the MSDN documentation for the Object.ToString Method.
public override string ToString()
{
return string.format("{0} {1}, {2}", firstName, secondName, dateOfBirth);
}
The code examples above may not compile because I typed them directly into the response window, but hopefully they will be useful as guidance. Hope this helps!

Read the toString requirement one more time, you're doing this wrong. What happens to your existing values when you call toString in your code now?
Also, check the two last property setters. Currently you're not preventing the user setting an invalid value.
You also need to create an instance of your class, and set initial values on it that you can return from toString.
Good luck, you're almost there :-)