c++ - Undefined reference to `typeinfo for class' and undefined reference to `vtable for class' -
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i'm dealing inheritance in c++. wanted write program addition , subtraction of 2 arrays. heres code:
#include <iostream> #include <cmath> #include <sstream> using namespace std; class root { protected : int size; double *array; public : virtual ~root() {} virtual root* add(const root&) = 0; virtual root* sub(const root&) = 0; virtual istream& in(istream&, root&) = 0; virtual int getsize() const = 0; virtual void setsize(int); virtual int getat(int) const = 0; }; class aa: public root { public : aa(); aa(int); aa(const aa&); root* add(const root& a); root* sub(const root& a); istream& in(istream&, root&){} int getsize() const; void setsize(int); int getat(int) const; }; class bb: public root { public: bb() { } bb(const bb& b) { } root* add(const root& a); root* sub(const root& a); istream& in(istream&, root&){} int getsize() const{} void setsize(int){} int getat(int) const{} }; aa::aa() { size = 0; array = null; } aa::aa(int nsize) { size = nsize; array = new double[size+1]; for(int i=0; i<size; i++) array[i] = 0; } root* aa::add(const root& a) { (int i=0; i<a.getsize(); i++) array[i] += a.getat(i); return new aa(); } root* aa::sub(const root& a) { } int aa::getsize() const { return size; } void aa::setsize(int nsize) { size = nsize; array = new double[size+1]; for(int i=0; i<size; i++) array[i] = 0; } int aa::getat(int index) const { return array[index]; } root* bb::add(const root& a) { return new bb(); } root* bb::sub(const root& a) { } int main(int argc, char **argv) { } but have strange errors:
/home/brian/desktop/temp/untitled2.o||in function `root::~root()':| untitled2.cpp:(.text._zn4rootd2ev[_zn4rootd5ev]+0xb)||undefined reference `vtable root'| /home/brian/desktop/temp/untitled2.o||in function `root::root()':| untitled2.cpp:(.text._zn4rootc2ev[_zn4rootc5ev]+0x8)||undefined reference `vtable root'| /home/brian/desktop/temp/untitled2.o:(.rodata._zti2bb[typeinfo bb]+0x8)||undefined reference `typeinfo root'| /home/brian/desktop/temp/untitled2.o:(.rodata._zti2aa[typeinfo aa]+0x8)||undefined reference `typeinfo root'| ||=== build finished: 4 errors, 0 warnings ===| dont know came from, dont how 'fix' them. in advance;)
root::setsize isn't declared pure virtual, means must defined. presumably, should pure other functions:
virtual void setsize(int) = 0; ^^^ if you're interested in gory details of why particular error: compiler needs generate class's virtual/rtti metadata somewhere and, if class declares non-pure, non-inline virtual function, generate in same translation unit function's definition. since there no definition, don't generated, giving error.
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