Pawn (AMXX) Tutorial (Variables) [12/31/2016]

Pawn is the language that AMXX codes are written on. Pawn routes AMXX to connect with Half Life's Engine. Pawn is written on C and AMXX ( Metamod Plugin ) is written on C++.

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Variables :

Variables are data types for holding data. (int, string, float..) . You can't use spaces when naming them, also they're case sensitive, that means that one capital character can change everything

new x // this is the variable x , it is empty as we haven't assigned any value
new x = 1 // now the x variable has the value "1"
new x = 0.5 // this is WRONG, you can't assign floats as variables.
new e,f,g,h // you can also declare multiple variables in just one line
new x=7, y=3 // and this

new var_name // correct naming
new var name // incorrect

new var_name
// this isn't the same as this
new Var_name

They can be local and global :

Local Variables :

They're created inside a function and can be used only in that function.

Global Variables : 

They're outside of functions and can be accessed in any function, a good example is a variable created for holding item price.

Example Local Variable : 

#include <amxmodx>

public plugin_init( ) {

register_plugin( "Test" , "1.0" , "DoNii" ) ;
register_clcmd( "say /showmyname" , "my_name" ) ;
}

public my_name( id ) {

new iName[ 32 ]; // our variable
get_user_name( id , name , charsmax( iName ) ) ;

client_print( id , print_chat , "Your Name Is %s", iName ) ;
}

Example Global Variable : 

#include <amxmodx>

new g_PriceM4A1 = 3000 // it's better to name it with the prefix g_ if it's global.

public plugin_init( ) {

register_plugin( "Test" , "1.0" , "DoNii" ) ;
register_clcmd( "say /priceofm4a1" , "M4A1PriceShow" ) ;
}

public M4A1PriceShow( id ) {

client_print( id , print_chat , "Price Of M4A1 Is $%d", g_PriceM4A1 ) ;
}


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Floats :

Float can store numbers with decimal values (0.1, 0.2535, 1.53, 96.12 etc..).

new Float:var = 0.5
new Float:var2 = 1.2  
new Float:var3 = 0.8

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Booleans :

Booleans or Bools, are variables which can only be assigned the value "true" or "false". Example

new bool:var //Declares a new variable "var" which is automatically false
new bool:var1 = true //Declares a new variable "var1" set to true

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Arrays :

Arrays are data types, that you can store in numbers and strings. Note that Arrays are zero-based. There are 1D and 2D arrays.

new Players[32] //This will declare a variable called "Players" which holds 32 numbers.
Players[0] = 5 //Set slot 0 to 5

new BadArray[a] // this is invalid because the slot must be a constant number ( 1,2,3,4,5.. )

new array[][] = // this is a 2D array, it's used for more readable and easy assign to bigger values, this is int method
{

      "5, 6, 7, 8"
      "2, 3, 4, 8"
      "5, 2, 0, 1"
}

new array[] = { "5,1,4" } // this is a 1D array, used for 1 line assignment.


2D Arrays :


//This declares an array with 50 rows and 50 columns.
new BigArray[50][50]

//this declares a floating point array with 25 rows and 10 columns.
new Float:BigArray[25][10]

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Strings : 

A string is an array of numbers that translate to ASCII (character) symbols. 

//This will declare a number array "myString" that contains the data "Hello".  
//It will have 6 slots, because there are 5 characters.  
//The last slot is reserved for the number 0, which tells the Pawn engine that it is a string.

new myString[] = "Hello" // in game it will output "Hello"
new myString[5] = "Hello" // will also output "Hello"
new myString[4] = "Hello" // will output "Hell" because we've made the slot 4, last slot is taken by the engine, so you need to count +1, if the word has 4 letters, you need to specify the slot 5, or just leave it blank, it will calculate itself.

new myString[6] // you can even do like this

myString[0] = 'H'
myString[1] = 'e'
myString[2] = 'l'
myString[3] = 'l'
myString[4] = 'o'
myString[5] = 0 // notice the null (0), it tells the engine where the string ends.

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Comments :

Comments ( // ) are ignored by the compiler, they are used to make the code more understandable , i've used comments on this tutorial. Example :

#include <amxmodx>

public plugin_init() {

register_plugin("Plugin", "1.0", "DoNii"); // this is a comment, compiler will not compile it
}

public client_putinserver(id) {

new szName[ 32 ] ;
get_user_name(id, szName, charsmax( szName ) ) ;

client_print( id, print_chat, "Your Name is : %s", szName ) ;
}


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Where can variables be helpful ?

Integers :
For holding prices, CVARs, count limits, offsets etc..

Bools : 
For checking if an item has been used, for stocks.

Arrays :
Holding CVARs, random integers, origins etc..