09.09.2015, 18:09
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Last edited by Dutheil; 10/09/2015 at 12:20 PM.
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Foreach & the functions handling of an iterator
Tutorial explaining the working of the include Foreach and the functions of iterations are being bonded.
This is my first english tutorial, so please correct me if syntaxes mean nothing.
This tutorial is available for Foreach 0.4.1.
Initiation:Tutorial explaining the working of the include Foreach and the functions of iterations are being bonded.
This is my first english tutorial, so please correct me if syntaxes mean nothing.
This tutorial is available for Foreach 0.4.1.
Foreach is a keyword that is found in many languages simplified today, unfortunately the Pawn is not allowed. This is why ****** spawned us a pretty include that it is intended.
Foreach is simply a loop running with iterators, but that I will explain to you a little later in the tutorial.
Concretely what it changes "for" and "while"? Much optimizing my friends !
The keyword foreach and an iterator :
I shock you if I say you that foreach is neither more nor less than a macro using for ?The functions handling iterators:
You're amazed, eh ?
But how "foreach" using "for", can it be faster than him ?
It comes with this story of iterators !
An iterator is simply an array in which each cell of this array contains the value -1, and are therefore invalid.
When you add a value positive and less than the size of your iterator, it will add to the first invalid cell of the array.
We must also take into account your array sorting the values of the smallest to the largest, this means that if you add the value 6 and then you add the value 5, your foreach will loop 2 times and come out first value 5, while we added after the value 6.
Here's an example, do not try to understand "Iter_Add" we will see it below :
This will printPHP Code:#include <a_samp>
#include <foreach>
new
Iterator:Test<10>;
main()
{
Iter_Add(Test, 6);
Iter_Add(Test, 5);
foreach(new i : Test)
{
printf("%d", i);
}
}
What if we had used "for" we would have looped 10 times. Of course, speed is calculable in nanoseconds, but you can imagine on a loop 500 or 2000 ? "Foreach" is really a useful!Code:5 6
Well, I hope I was understood.
In fact, "foreach" is nothing without iterators, it is only a macro similar to some that if I return to my example:
Simply, you do not have to break your head with comparisons. The include may seem complex only at the instructions of the functions handling iterators. Fortunately, Dutheil studied them for you and will explain them to you, we are left after the pubclicity !PHP Code:new
Test[10] = {-1, ...};
main()
{
Test[0] = 5;
Test[1] = 6;
for(new i = 0; i < 10 && Test[i] != -1; i++)
{
printf("%d", i);
}
}
Function » Iter_Add:
This function adds a value to an iterator, it contains two parameters :It may return 2 values :
- The iterator name
- The value
Example of use :
- 0 - If the value is less than 0 or greater than the size of the iterator or iterator is already full
- 1 - If the function was successfully executed
Here we add the value 6 to the iterator Test.PHP Code:Iter_Add(Test, 6);
Function » Iter_Remove:
This function allows you to remove a value from an iterator, it contains two parameters :It may return 2 values :
- The iterator name
- The value
Example of use :
- 0 - If the value is less than 0 or greater than the size of or the iterator that the iterator is empty
- 1 - If the function was successfully executed
Here it removed the value 6 to the iterator Test.PHP Code:Iter_Remove(Test, 6);
Function » Iter_Free:
This function returns the smallest value that is not in the iterator, it contains one parameter :It can return two types of value :
- The iterator name
Example of use :
- -1 - If the iterator is full
- The smallest value that is not in the iterator
If the iterator contains the values 0, 1, 3, 5, 8, the function will return 2.PHP Code:new
variable = Iter_Free(Test);
Function » Iter_Contains:
This function of whether an iterator contains a specified value, it contains two parameters :It may return 2 values :
- The iterator name
- The value
Example of use :
- 0 - If the iterator contains no value
- 1 - If the iterator contains the value
If the iterator contains the values 0, 2, 4, 6, 8, the function will return 1 and code therefore display "Yes !".PHP Code:if(Iter_Contains(Test, 6))
{
print("Yes !");
}
Function » Iter_Count:
This function returns the number of values in an iterator, it contains one parameter :Example of use :
- The iterator name
If the iterator contains the values 0, 1, 3, 4, 7, the function will return 5.PHP Code:printf("%d", Iter_Count(Test));
Function » Iter_Random:Iterators ready for use:
This function returns a random value contained in an iterator, it contains one parameter :It can return two types of value :
- The iterator name
Example of use :
- -1 - If the iterator is empty
- A random value contained in the iterator
Well here I can not tell you what the function returns, it is randomPHP Code:print("%d", Iter_Random(Test));
!
Here is a list of iterators ready to be used with foreach :
- Player - Iterator of connected players.
- Bot - Iterator of connected bots.
- NPC - Alias of Bot.
- Character - Iterator of connected players and bots.
Two constants are available to you, they are to be defined before including foreach.
FOREACH_NO_BOTS
Does not create the iterators Bot NPC and CharacterFOREACH_NO_PLAYERS
Does not create the iterator Player and Character
__________________________________________________ __
Tutorial over, if you think I forgot an important point, let me know after the subject.
Go kisses!
Tutorial over, if you think I forgot an important point, let me know after the subject.
Go kisses!
