What is the correct full syntax for creating a list in MQL5?

[Jimmy9618]

Sorry for the simple question, I am very new to MQL5. I know how to create a generic array, but am now trying to create a list of undefined size, which values can be added to. Most of the literature I read seemed to go over my head

[Gerard Willia G J B M Dinh Sy]

Good morning

The help on this forum doesn't work like that.

Show your code with or without errors, but show your code, and maybe you will get help

[Drazen Penic]

Jimmy9618:
Sorry for the simple question, I am very new to MQL5. I know how to create a generic array, but am now trying to create a list of undefined size, which values can be added to. Most of the literature I read seemed to go over my head

Read the documentation for Standard Library -> Data Collections

There you will find CList, CArray, and CTree.

Also, read the documentation for the whole standard library. 

[Lorentzos Roussos]

Jimmy9618:
Sorry for the simple question, I am very new to MQL5. I know how to create a generic array, but am now trying to create a list of undefined size, which values can be added to. Most of the literature I read seemed to go over my head

Besides @Drazen Penic 's points you can do it yourself too .

Let's say you want a one type solution so as to not mix templates into the example.

long tickets[];

That is your list of tickets with an unknown size

You need 3 things 

Adding to your list

//you receive the array where you want to add the item and its value in the function 
int add(long &array[],long add_this){
//calculate the new size of the array
int new_size=ArraySize(array)+1;
//apply the new size
ArrayResize(array,new_size,0);
//fill in the new element which sits at size-1
array[new_size-1]=add_this;
//and return the address of the new element or the total elements
return(new_size-1);
}

Removing from your list

//you send the array and the index of the item you want to remove
int remove_unordered(long &array[],int remove_index){
//you calculate the new size 
int new_size=ArraySize(array)-1;
//now the new size points to the last element as well , interesting
//so take the last element and place it in the index you no longer need
array[remove_index]=array[new_size];//because new size points to the last element
//aand shrink it
ArrayResize(array,new_size,0);
//return the size
return(new_size);
}

And the most fun of all , finding one item in your list

//you provide the array and what value you are looking for
int find(long &array[],long find_this){
for(int i=0;i<ArraySize(array);i++){
//if the value matches what you are looking for return the index
if(array[i]==find_this){
return(i);    
}
}
//you return -1 if you find nothing
return(-1);
}

So in a use scenario you would add a ticket like this :

//you send the name of the array , tickets , and the ticket 
add(tickets,4235315631);

and so on

 

[Jimmy9618]

Lorentzos Roussos #:

Besides @Drazen Penic 's points you can do it yourself too .

Let's say you want a one type solution so as to not mix templates into the example.

That is your list of tickets with an unknown size

You need 3 things 

Adding to your list

Removing from your list

And the most fun of all , finding one item in your list

So in a use scenario you would add a ticket like this :

and so on

 

Exactly the kind of help I was looking for. Thank you very much!!