c++ array

[Chunchunmaru 6]

hi everyone,

 

i use that with lua but i need that c++ code. How can i use that ? 

Lua : 

list = 

{

                [5]        = { 110,123123,1,false,0},
                [150]        = { 1103,1232123,1,false,0},
                [3500]        = { 1120,123123,1,true,0},
                [12]        = { 1110,123123,1,false,0},

}

 

i want use with c++ just like lua list[5][1]

[Ikarus_ 2426]

First of all you should create the data structure you need, which Lua does automatically but the c++ no.

 

struct MyStructData
{
	int MyInt;
	BYTE MyByte;
	bool MyBool;
	char szName[24];
}

 

Then you have to decide how you want to use this data.
You can use them in a list (optimized if you have to remove and put members very often)
You can use them in a vector (optimized for random access)
You can use them in a map (optimized with key search -> value)

 

example of list :

struct MyStructData
{
	int MyInt;
	BYTE MyByte;
	bool MyBool;
	char szName[24];
}

std::list<MyStructData> MyList; //I declare a list and set it a type of data (in this case mystructdata)


//i declare a new MyStructData and set it value
MyStructData Example;
Example.MyInt = 0;
Example.MyByte = 0xFF;
Example.MyBool = false;
strncpy( Example.szName , "My string is this." , sizeof(Example.szName) );

//add my new data in list
MyList.push_back( Example );

//remove last member inserted
MyList.pop_back();

 

 

example of vector  (same of list)

struct MyStructData
{
	int MyInt;
	BYTE MyByte;
	bool MyBool;
	char szName[24];
}

std::list<MyStructData> MyVector; //I declare a vector and set it a type of data (in this case mystructdata)


//i declare a new MyStructData and set it value
MyStructData Example;
Example.MyInt = 0;
Example.MyByte = 0xFF;
Example.MyBool = false;
strncpy( Example.szName , "My string is this." , sizeof(Example.szName) );

//add my new data in vector
MyVector.push_back( Example );

//remove last member inserted in vector
MyVector.pop_back();

 

 

The different between list and vector is :
List is efficient to add and remove member in list , is not efficient for access to members of the list .

Vector is efficient to do the random access ( [5] , [100] , [150] )

Spoiler

Example of access to member memory for vector and list :

//if vector size > x :
myVec[x].MyInt = 10;

myVec[x].MyBool = true;




//for list i need a iterator.

std::list<MyStructData>::iterator it = MyList.begin(); //to declare a iterator the sintax is std::CONTEINER_TYPE<DATA_TYPE>::iterator         MyList.begin() -> pointer to first member of list

for( /* already declared it */  ; it  != MyList.end()  ; it++)  //this for cicle scrolls the entire list 
{
	if(it->MyInt == 10) //use -> because it is a pointer 
	{
		it->MyBool =  true;
	}
}

 

 

Example of map:

struct MyStructData
{
	int MyInt;
	BYTE MyByte;
	bool MyBool;
	char szName[24];
}

std::map<BYTE , MyStructData> MyMap; //I declare a map and set it a type of data and a type of key (in this case mystructdata and Byte)


//i declare a new MyStructData and set it value
MyStructData Example;
Example.MyInt = 0;
Example.MyByte = 0xFF;
Example.MyBool = false;
strncpy( Example.szName , "My string is this." , sizeof(Example.szName) );


//insert new member in map
BYTE key = 0xFA;

MyMap.insert( std::make_pair( key , Example ) ); // insert key 0xFA (aka 250 in decimal) with value Example

//access to member

MyMap[250].MyInt = 100;
MyMap[250].MyBool = true;

//access in member by key with iterator
std::map<BYTE , MyStructData>::iterator it = MyMap.find(250);
it->second.MyInt = 100;
it->second.MyBool = true;

//access to all member of map
std::map<BYTE , MyStructData>::iterator another_it = MyMap.begin();
for( ; another_it != MyMap.end() ; another_it++)
{
	if(another_it->second.MyInt != 100)
	{
		another_it->second.MyBool = false;
	}
}

 

 

There are many possibilities, you have to find the most useful one for your needs.

 

You can understand more about it by enjoying STL Conteiner

 

Bye Bye