- Multi means many
Thread means process
- Process indicates either a part of a program or a complete program also
- Multi threading is a concept of executing more than one process simultaneously.
- Multi threading is used to develop parallel processing
Pentium iv 4.3 GHZà43 Lakhs of instructions(cycle ) within 1min
Speed
- Sharing CPU cycles efficiently is also called as “Multi Threading”.
- Operating system allocates a set of as cles based on the priority(importance)of the process.
Ctrl+ Alt+ del
- Based on above statement, the os are divided into two types:-
Single Threaded
DOS UNIX
given to one app only
Multi Threading
- If o/s handles only one process at a time, then it is called as “single thread os”.
- Multi thread os handles more than one process also
- To work with multi threading, NET introduced
System. Threading name space
- Classes of system. Threading name space
- a) Thread: Used to maintain the life asele of the threads
- b) Thread start: Used to create the threads.
- c) Mutex: Used in thread synchronization
Thread life cycle:-
Four steps for writing threading applications:_
- Write a class with methods
Class test
{
Public vaid print(){}
}
- Create an object for thread start delegate with the address of a function
Syntax:- Test t = new test();
Thread start ts=new thread start(t.print);
- Create a thread with the help of thread start object
Thread tr=new thread(ts);
Start the thread
Tr. start()
Example1:-
A program to execute two for loops simultaneously
Open console application project
Using system. Threading;
code in GD
Class test
{
Public static vold p1()
{
For (int i=1; i<=10;i++)
{
Console. write(I+””);
Thread . sleep(500);
}//for
}//p1
Public static void p2()
{
For(int k=11;k<20;k++)
{
Console. write link(k);
Thread. sleep(500)//500 millisec
}//for
}//p2
}//test
Code for main method:-
Thread start ts1=new thread start (Test.p1)
Thread start ts2=new thread start (Test.p2)
Thread t1=new thread (ts1)
Thread t2=new thread (ts1)://here ts1
T1.start()
T2.start()
Console.Read key();
T1.suspend();
Console. Read key();
T1.Resume();
Console. Read key ();
o/p : 112233----2020
Thread synchronization:-
1.Thread synchronization is the concept of allowing only one thread at a time into one process
2.It process is busy, threads need to wait in the queue
3.Waiting threads will be executed based on prlority
- Mutex is a class which controls waiting threads with the help of wait one() and release mutex()
OBS:
5.The code which is written in between wait one()and release mutex()is called as synchronized code.
A Program to print ”ALL THE BEST”3 TIMES WITH THE HELP OF THREADING:
{
Console. write(“ALL”);
Console. write(“THE”);
Console. write(“Best”);
}
open console application project
Using system. Threading;
Code in GD
Class program
{
Static mutex m = new mutex();
Class test
{
Public static void print()
{
- wait one();
console. write(“ALL”);
Thread. sleep(1000);
Consote. write(“THE”);
Thread .sleep(1000);
Console. write(“BEST”);
Thread. sleep(1000);
Console. Write line();//for new line
Thread. sleep(1000);
- Release mutex();
}//test
Code for main method:-
{
Thread start ts=new thread start(test. print);
Thread start t1=new thread (ts);
Thread start t2=new thread (ts);
Thread start t3=new thread (ts);
T1.Start();
T2.Start();
T3.Start();
Console. Read key();
}
Pointers:-
Why we use pointers?
For fast accessing
Fig(a)
Accesing ’i’ value is fast when compared to pointer variable, but it is not in this case fast.
Char*p 2B
Double*p 2B
Logic is m/c of o/s they are unmanaged code.
The size of the pointers varies or dependent on the o/s, so they are unmanaged code, so c#.net only supports pointers but not implemented.
- Pointer holds the address of a variable.
- Pointer are unmanaged code in c#.net.
- Pointer are also called as unsafe code.
Unsafe is a key word
Pointers logic must be the part of unsafe block only
Pointer size varies from o/s to o/s
Generally o/s are divided into 3 types
Un managed code is not all recommended In c# .net it we want to use in c# by using un sate key word
Ex:- Place a button on the form
{
Un sate
{
Int iz 90;
Int*p;
P=&I;
Int k;
K=*p**p;
MBS(K+””);
}
By pressing f5 if gives warning that you are using un state code. Please in form to CLR to execute unsafe code.
Go to project propertiesbuildàCheck
Menu
“Allow un sate code”
Check Box
Execute the project
Inter+ view Internal look-Behavior
subject
time sense
Body language
confidence