Question

‘initPhysics’ was not declared in this scope.

I have simplified my program as much as I could; here it is:

helloworld.hpp

#ifndef HELLOWORLD_HPP
#define HELLOWORLD_HPP

class testWorld {
    public:
        testWorld() {}
        ~testWorld() {}
        void initPhysics();
};
#endif

hello.cpp

#include "helloworld.hpp"
#include <iostream>

using namespace std;

void testWorld::initPhysics() {
    cout << "Initiating physics..." << endl;
}

int main(int argc,char** argv) {
    cout << "Hello World!" << endl;
    testWorld* world;
    world = new testWorld();
    world<-initPhysics();
    return 0;
}

I compile with the command

g++ -c hello.cpp

and get the error

hello.cpp: In function ‘int main(int, char**)’:
hello.cpp:14:21: error: ‘initPhysics’ was not declared in this scope

Why doesn’t the compiler see the declaration of initPhysics, even though I included helloworld.hpp?

Answer 1

It should be world->initPhysics(), not world<-initPhysics()

Your version is being read as the expression “world is less than -1 multiplied by the result of the global function initPhysics()” and it’s that global function that it can’t find.

And although this is obviously test code, I’d just like to point out that if you allocate an object with new, you must explicitly delete it somewhere.