using System.Net.Sockets;
using System.IO;
using System.Text;
using System.Web;
public partial class _Default: System.Web.UI.Page {
protected void btnCheck_Click(object sender, EventArgs e) {
TcpClient tClient = new TcpClient("gmail-smtp-in.l.google.com", 25);
string CRLF = "\r\n";
byte[] dataBuffer;
string ResponseString;
NetworkStream netStream = tClient.GetStream();
StreamReader reader = new StreamReader(netStream);
ResponseString = reader.ReadLine();
/* Perform HELO to SMTP Server and get Response */
dataBuffer = BytesFromString("HELO KirtanHere" + CRLF);
netStream.Write(dataBuffer, 0, dataBuffer.Length);
ResponseString = reader.ReadLine();
dataBuffer = BytesFromString("MAIL FROM:<[email protected]>" + CRLF);
netStream.Write(dataBuffer, 0, dataBuffer.Length);
ResponseString = reader.ReadLine();
/* Read Response of the RCPT TO Message to know from google if it exist or not */
dataBuffer = BytesFromString("RCPT TO:<" + TextBox1.Text.Trim() + ">" + CRLF);
netStream.Write(dataBuffer, 0, dataBuffer.Length);
ResponseString = reader.ReadLine();
if (GetResponseCode(ResponseString) == 550) {
Response.Write("Mai Address Does not Exist !<br/><br/>");
Response.Write("<B><font color='red'>Original Error from Smtp Server :</font></b>" + ResponseString);
}
/* QUITE CONNECTION */
dataBuffer = BytesFromString("QUITE" + CRLF);
netStream.Write(dataBuffer, 0, dataBuffer.Length);
tClient.Close();
}
private byte[] BytesFromString(string str) {
return Encoding.ASCII.GetBytes(str);
}
private int GetResponseCode(string ResponseString) {
return int.Parse(ResponseString.Substring(0, 3));
}
} Write, Run & Share C# code online using OneCompiler's C# online compiler for free. It's one of the robust, feature-rich online compilers for C# language, running on the latest version 8.0. Getting started with the OneCompiler's C# compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as C# and start coding.
OneCompiler's C# online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.
using System;
namespace Sample
{
class Test
{
public static void Main(string[] args)
{
string name;
name = Console.ReadLine();
Console.WriteLine("Hello {0} ", name);
}
}
}
C# is a general purpose object-oriented programming language by Microsoft. Though initially it was developed as part of .net but later it was approved by ECMA and ISO standards.
You can use C# to create variety of applications, like web, windows, mobile, console applications and much more using Visual studio.
| Data Type | Description | Range | size |
|---|---|---|---|
| int | To store integers | -2,147,483,648 to 2,147,483,647 | 4 bytes |
| double | to store large floating point numbers with decimals | can store 15 decimal digits | 8 bytes |
| float | to store floating point numbers with decimals | can store upto 7 decimal digits | 4 bytes |
| char | to store single characters | - | 2 bytes |
| string | to stores text | - | 2 bytes per character |
| bool | to stores either true or false | - | 1 bit |
datatype variable-name = value;
When ever you want to perform a set of operations based on a condition or set of few conditions IF-ELSE is used.
if(conditional-expression) {
// code
}
else {
// code
}
You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.
Switch is an alternative to If-Else-If ladder.
switch(conditional-expression) {
case value1:
// code
break; // optional
case value2:
// code
break; // optional
...
default:
// code to be executed when all the above cases are not matched;
}
For loop is used to iterate a set of statements based on a condition.
for(Initialization; Condition; Increment/decrement) {
// code
}
While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.
while(condition) {
// code
}
Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.
do {
// code
} while (condition);
Array is a collection of similar data which is stored in continuous memory addresses. Array values can be fetched using index. Index starts from 0 to size-1.
data-type[] array-name;
Method is a set of statements which gets executed only when they are called. Call the method name in the main function to execute the method.
static void method-name()
{
// code to be executed
}