Thread: Problems with vectors of objects!

I am currently programming a digital circuit simulator program (uni coursework) ...I have created a vector of objects...

vector <LogicGate*> theCircuit;

Inside logic gate there are functions for all logic gates! ...then there are seperate sub-classes that are derrived from class LogicGate to over-ride some functions to give the ability to create different types of logic; and, or, xor, not. My vector can contain any of these classes, this works fine...

Code:

int Circuit::addGate(int inType){
	switch(inType){
	  case 0 : theCircuit.push_back(new InputGate(newID(), 0)); return 0;
	  case 1 : theCircuit.push_back(new InputGate(newID(), 1)); return 0;
	  case 2 : theCircuit.push_back(new AndGate(newID(), 2));   return 0;
	  case 3 : theCircuit.push_back(new OrGate(newID(), 3));    return 0;
	  case 4 : theCircuit.push_back(new XorGate(newID(), 4));   return 0;
	  case 5 : theCircuit.push_back(new NotGate(newID(), 5));   return 0;
	  default : return -1;
	}
}
// NOTE: newID() is a small function that generates (and then returns) unique id codes.
// To give you an idea what the values are for constructing logic gates; the constructor for the andgate class...

// AndGate::AndGate(int inID, int inType){ .. sets id and logic gate type here .. }

So now i have my vector with the above logic gate objects inserted! ...I thought therefore, that i could easily do the following...

Code:

for (int i=0; i<theCircuit.size(); i++){
  // is current gate an input gate?
  if (theCircuit.at(i).getType() != 0) { ...some code here... }
}

with getType() function being declared in class LogicGate...

Code:

class LogicGate{
private:
    int gateType; // The type of logic gate
    int gateID;   // The ID for the logic gate
    int pID1;     // The first parent for the logic gate
    int pID2;     // The second parent for the logic gate
    int input1;   // The first input value for the logic gate
    int input2;   // The second input value for the logic gate
    int output;   // The output value for the logic gate
public:
  // Class Methods:
  void setID(int);		   // sets the gate ID number
  int getType();			   // returns the gate type code
  void setType(int);		   // sets the gate type code
  int getID();               // returns gates ID
  int getPID1();             // returns gates first parent ID
  int getPID2();             // returns gates second parent ID
  void setPID1(int);         // sets ID of gates first parent
  void setPID2(int);         // sets ID of gates second parent
  void setInput1(int);       // sets gates first input value
  void setInput2(int);       // sets gates second input value
  int getInput1();           // returns value of first input
  int getInput2();           // returns value of second input
  // Virtual Methods:
  virtual int getOutput();   // returns gates output value 
};

However; at compilation i get the error...

Code:

:\WORK\CIRCUIT.CPP(100) : error C2228: left of '.getType' must have class/struct/union type

Its confusing, because to me it appears that this should work fine!!! ...I tried a simpler version using vectors of objects and that worked fine, i could access all the objects functions using the vector.at(x).functionName() with no problems at all!!! so what is going on here??? ...anyone know what i am doing wrong???

Cheers!!! Matt..

Your vector contains pointers to logic gates
use

Code:

vector.at(x)->functionName();

Kurt

DOH!!!! ...I had even put that in my little tester program!!!! arrrggghhh!!! I swear this programming nonsense is making me insane in the membrain!!! Cheers man!!!! such little problems!!!!! arrrggghhhh!!!!!

Originally Posted by bobthebullet990

DOH!!!! ...I had even put that in my little tester program!!!! arrrggghhh!!! I swear this programming nonsense is making me insane in the membrain!!! Cheers man!!!! such little problems!!!!! arrrggghhhh!!!!!

You shure should stop trying to program.