There’s no mystery here, the linker is telling you that you haven’t defined the missing symbols, and you haven’t. Similarity::Similarity() or Similarity::~Similarity() are just missing and you have defined the others incorrectly, not etc. etc. The second one is a function called readData, only the first is the readData method of the Similarity class. To be clear about … Read more
If you are interested in finding out whether a variable has been declared regardless of its value, then using the in operator is the safest way to go. Consider this example: But this may not be the intended result for some cases, since the variable or property was declared but just not initialized. Use the in operator for a … Read more
If you are interested in finding out whether a variable has been declared regardless of its value, then using the in operator is the safest way to go. Consider this example: But this may not be the intended result for some cases, since the variable or property was declared but just not initialized. Use the … Read more
What are you using to compile this? If there’s an undefined reference error, usually it’s because the .o file (which gets created from the .cpp file) doesn’t exist and your compiler/build system is not able to link it. Also, in your card.cpp, the function should be Card::Card() instead of void Card. The Card:: is scoping; … Read more
Your header file Hash.h declares “what class hash should look like”, but not its implementation, which is (presumably) in some other source file we’ll call Hash.cpp. By including the header in your main file, the compiler is informed of the description of class Hash when compiling the file, but not how class Hash actually works. When the linker tries to create the entire program, … Read more