Inheritance from a Template Class [closed] - c++

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I have a template class,in fsm.h file
and derived class in derivata.h file;
the compiler throws errors:
derivata.h: In constructor ‘deri::deri()’:
derivata.h:46: error: no matching function for call to ‘fsm<pin_steps>::fsm()’
fsm.h:30: note: candidates are: fsm<step_type>::fsm(step_type) [with step_type = pin_steps]
fsm.h:12: note: fsm<pin_steps>::fsm(const fsm<pin_steps>&)
fsm.h:
#ifndef FSM_H_
#define FSM_H_
template<class step_type> class fsm {
protected:
step_type step;
step_type step_old;
step_type step_tmp;
bool step_pulse;
char name[256];
public:
fsm(step_type);
void set_name(char *parent, char *myname);
void test();
virtual void update(){cout << "base\n";};
void show(){cout << step << ' ' << step_tmp << '\n'; };
void init(step_type st_current) {step = st_current;};
//virtual ~fsm();
};
//constructor
template <class step_type> fsm<step_type>::fsm(step_type) {
step = step_old = step_tmp = (step_type)0 ;
step_pulse = false;
}
template <class step_type> void fsm<step_type>::set_name(char *parent, char *myname) {
sprintf(name, "%s.%s", parent, myname);
}
template <class step_type> void fsm<step_type>::test() {
if (step != step_old) {
step_pulse = true;
step_tmp = step_old;
} else step_pulse = false;
step_old = step;
}
#endif /* FSM_H_ */
and a derived class from template class:
#include "fsm.h"
#ifndef DERIVATA_H_
#define DERIVATA_H_
enum taglio_steps {
ST_TAGLIO_CHECK_MOTORE,
ST_TAGLIO_ZERO_MOTORE,
ST_TAGLIO_WAIT_ZERO_MOTORE
};
enum pin_steps {
ST_PIN_BOOT,
ST_PIN_RETURN
};
class deri : public fsm<pin_steps>{
private:
bool cmd_prelevamento_done;
bool cmd_scorrimento_done;
float posizione_pinza_i;
float posizione_pinza_f;
public:
deri(){
cmd_prelevamento_done = false;
cmd_scorrimento_done = false;
posizione_pinza_i = 0;
posizione_pinza_f = 0;
};
void update(){cout << "deri\n";};
// virtual ~deri();
};
#endif /* DERIVATA_H_ */

Answer 1

Your base class doesn't have a non-parameter constructor, but in your derived class you are calling one (it is called automatically).
Change this:
deri(){
cmd_prelevamento_done = false;
cmd_scorrimento_done = false;
posizione_pinza_i = 0;
posizione_pinza_f = 0;
};
To this (pseudocode, I am not sure about correct syntax, I do not use this too often):
deri(): fsm<pin_steps>(ST_PIN_BOOT) {
cmd_prelevamento_done = false;
cmd_scorrimento_done = false;
posizione_pinza_i = 0;
posizione_pinza_f = 0;
};

Answer 2

The base class doesn't have a default constructor which is needed if (in constructor of a derived class) you don't specify which one should be called. If you dont' want fsm to be default-constructible, do this instead:
deri() : fsm(ST_PIN_BOOT) // call fsm::fsm(pin_steps)
{
// ...
}

Answer 3

The compiler error seems pretty clear. You are not calling the fsm<> constructor, and there are no default constructors for fsm. Your options are thus:
Create a default constructor: fsm::fsm() { ... }
Or, more likely in your case: call the constructor in the deri initalization list, like this:
deri() : fsm(step_type_here)
{
cmd_prelevamento_done = false;
cmd_scorrimento_done = false;
posizione_pinza_i = 0;
posizione_pinza_f = 0;
};
I would also recommend putting the other member variable initializations in the initializer list too.

Answer 4

That code is too big but i think you need a default constructor in the base class. Looks like Something like this
public:
fsm(); //added
fsm(step_type);
void set_name(char *parent, char *myname);
void test();
virtual void update(){cout << "base\n";};
void show(){cout << step << ' ' << step_tmp << '\n'; };
void init(step_type st_current) {step = st_current;};
//virtual ~fsm();