Re: Problem with adding a data into a vector
oktayarslan@gmail.com writes:
Hi all;
I have a problem when inserting an element to a vector. All I want is
reading some data from a file and putting them into a vector. But the
program is crashing after pushing a data which has string value. I
really do not understand why push_back() function is trying to remove
previously inserted data.
Thanks for any help
class VLProperty
{
public:
enum Aircraft{
BO105,
F16
};
enum Type{
INT,
BOOL,
LONG,
FLOAT,
DOUBLE,
STRING,
UNSPECIFIED
};
};
This is not a class.
What if you have an Aircraft named the LONG ?
Better write:
namespace Aircraft {
enum Aircraft {
Bo105, F16, Unspecified }};
namespace Type {
enum Type {
Int, Bool, Long, Float, String, Unspecified }};
and: Type::Int, Type::Unspecified, Aircraft::Unspecified, Aircraft::F16.
But see below, you shouldn't need these enums.
struct VLPropertyData {
unsigned id;
// While the type isn't transmitted, it is needed for the destructor
VLProperty::Type type;
union{
int int_value;
float float_value;
char* string_value;
};
//std::string string_value;
VLPropertyData()
{
std::cout << "new data\n";
}
~VLPropertyData() {
if ((type == VLProperty::STRING) || (type ==
VLProperty::UNSPECIFIED))
{
std::cout << string_value << " is deleted" << std::endl;
delete [] string_value;
}
}
};
This is very wrong.
class Data {
protected:
unsigned id;
public:
virtual ~Data(){
std::cout<<"data id "<<id<<" is deleted"<<std::endl;
};
};
class Int:public Data {
protected:
int value;
public:
Int(int aValue):value(aValue){}
Int(float aValue):value(aValue){}
Int(string aValue):value(atoi(aValue)){} // for example, if you need it.
virtual ~Int(){
std::cout<<"An Int ";
}
};
class String:public Data {
protected:
std::string value;
public:
String(int aValue){ std::ostringstream s; s<<aValue; value=s.str(); } // for example, if you need it.
String(string aValue):value(aValue){}
virtual ~String(){
std::cout<<"A String ";
// There's nothing to do to delete a std::string, it'll be done automatically!
}
};
etc for the other types.
class Property{
protected:
std::string name;
Data* value;
public:
Property(std::string aName,int aValue):name(aName),value(new Int(aValue){}
Property(std::string aName,std::string aValue):name(aName),value(new String(aValue){}
...
virtual ~Property(){
delete value;
}
};
property[i++]=Property::Property("wheels",4");
property[i++]=Property::Property("name","a string");
property[i++]=Property::Property("pi",3.14);
if (VLMultiplayMgr::sIdPropertyDescMap.count(propertyData.id) > 0)
{
propertyData.type = VLMultiplayMgr::sIdPropertyDescMap[propertyData.id].type;;
// How we decode the remainder of the property depends on the type
switch (propertyData.type) {
case VLProperty::INT:
case VLProperty::BOOL:
case VLProperty::LONG:
propertyData.int_value = atoi(value.data());
This is wrong. Each type of data is written with a specific syntax.
This is wrong because you are giving the same bit of information
twice, once in the type, and another time in the syntax. What would happen if you had:
VLProperty::INT "\"toto\""
VLProperty::INT "3.14"
VLProperty::INT "42"
Only the last couple is valid. Forget the type! Analyse the token,
and infer the type automatically:
"false" --> new Bool(false);
"\"toto\"" --> new String("toto");
"3.14" --> new Float(3.14);
"42" --> new Int(42);
If you want to do it correctly, have a look at lex or flex.
Otherwise if you want to do a slow Q&D kludge, you can use regexps:
if(match("^ *false $",value)){
return new Bool(false);
}else if(match("^ *true $",value)){
return new Bool(true);
}else if(match("^[0-9][0-9]*$",value)){
return new Int(atoi(value));
}else if(match("^[0-9][0-9]*\\.[0-9][0-9]*\\([Ee]\\(+\\|-\\)\\?[0-9][0-9]*$",value)){
return new Float(atof(value));
}else if(match("^\"\\([^\"]*\\|\\.\\)*\"$",value)){
return new String(unwrapString(value));
....
}else{
error("lexical error: invalid token: ",value);
}
--
__Pascal Bourguignon__