Pure virtual function error - c++

Question

I receive this error:
In function 'bool detect_feedback(AudioEffect*)':
54:30: error: cannot convert 'std::shared_ptr<AudioEffect>' to 'AudioEffect*' in assignment
55:16: error: cannot convert 'std::shared_ptr<AudioEffect>' to 'AudioEffect*' in assignment
55:40: error: cannot convert 'std::shared_ptr<AudioEffect>' to 'AudioEffect*' in assignment
The code is as follows:
#include<stdlib.h>
#include<iostream>
#include<memory>`
//BASE CLASS
// audio and have a subsequent effect (next).
struct AudioEffect
{
virtual ~AudioEffect() = default;
virtual void process(float* buf, size_t num) = 0;
std::shared_ptr<AudioEffect> next;
};
//DERIVING MULTIPLE AUDIO-EFFECTS
//Noise Gate
struct NoiseGate: public AudioEffect
{
float threshold;
void process(float *buf, size_t num)
{
if (*buf > threshold)
*buf = threshold;
}
};
//Gain Boost
struct GainBoost: public AudioEffect
{
float signal;
void process(float *buf, size_t num)
{
*buf = *buf + signal;
}
};
//Compressor
struct Compressor: public AudioEffect
{
float offset;
void process(float *buf, size_t num)
{
*buf = *buf - offset;
}
};
//Function
// Implement a function that checks if there is a feedback loop
// in the effects chain.
//... detect_feedback(...)
//{
//}
bool detect_feedback (AudioEffect *ae)
{
AudioEffect *p, *q;
for (p = ae;p != NULL; p = p->next)
for (q = p->next; q != NULL; q = q->next)
if (typeid(*p) == typeid(*q))
return true;
return false;
}
//MAIN
int main(int argc, char *argv[])
{
return 0;
}

Answer 1

You can not assign a shared_ptr to a raw pointer. You need to use the .get() method to obtain a raw pointer.
(p->next).get()