10.25 C++

#include <iostream>

using namespace std;

class myvector{
private :
int *p;
int size;
int next;
public :
myvector(){
p = NULL, size = next = 0;
}
myvector(int n){
size = n;
p = new int[n];
next = 0;
}
myvector(int n, int v){
size = n;
p = new int[n];
next = n;
for(int i = 0; i < n; i++)
p[n] = v;
}
~myvector(){
if (p != NULL) delete[] p;
}
int get_size(){
return next;
}
int get_maxsize(){
return size;
}
int get_value(int i){
return p[i];
if(i <0 || i >= next){
cout << "index out of range" << endl;
return -1;
}
}
void set_value(int i , int v){
if(i < 0 || i >= next){
cout << "index out of range" << endl;
}
else p[i] = v;
}
void push_back(int v){
if (size == next){
if(p == NULL){
p = new int[10];
size = 10;
}
else
{
int *q = new int[size *2];
for(int i =0;i<size;i++){
q[i]=p[i];
}
delete[] p;
p = q;
size = size*2;
}
}
p[next++] = v;
}
void clear(){
delete[] p;
size = next = 0;
}
};

void read_data(myvector &m){
        int value;
        m.clear();
        while(true){
                cin >> value;
                if(value < 0) break;
                m.push_back(value);
        }
}
void process(myvector &m){
        int sum = 0;

        for(int i = 0;i<m.get_size();i++){
                sum += m.get_value(i);
        }
        cout << (double)sum / m.get_size() << endl;
}

int main(){
myvector a, b(20), c(16,100);

cout << a.get_maxsize() << "," << a.get_size() << endl;
cout << b.get_maxsize() << "," << b.get_size() << endl;
cout << c.get_maxsize() << "," << c.get_size() << endl;

read_data(a); process(a);
read_data(a); process(a);

return 0;
}