Диапазон значений массива, среднее значение

#include <vector>
using std::vector;
class Zadacha
{
public:
void printmenu();
void dobavit ();
void diapazon() ;
void srznach ();
private:
vector<int> measures;
 
};

#include <iostream>
#include <vector>
 
#include "zadacha.h"
using namespace std;
void Zadacha::printmenu()
{
cout<<"1 Dobavit"<<endl<<"2 Diapazon"<<endl<<"3 Srednee znachenie"<<endl<<"4 Exit"<<endl;
}
void Zadacha::dobavit()
{
int data;
cin>>data;
measures.push_back(data);
}
void Zadacha::diapazon()
{
int min=measures[0];
int max=measures[0];
for (int i=0;i<measures.size();++i)
{
if (measures[i]<min)
{
min=measures[i];
}
if (measures[i]>max)
{
min=measures[i];
}
}
cout<<min<<' '<<max;
}
void Zadacha::srznach ()
{
float srz=0;
for (int i=0;i<measures.size();++i)
{
srz=srz+measures[i];
}
srz=srz/measures.size();
cout<<srz;
}

#include <iostream>
#include <fstream>
 
#include <vector>
#include "zadacha.h"
using namespace std;
 
int main()
{
Zadacha zadacha;
 
char op;
while (!(op='4'))
{
zadacha.printmenu();
cin>>op;
switch (op)
 
{
case '1':zadacha.dobavit();break;
case '2':zadacha.diapazon();break;
case '3':zadacha.srznach();break;
case '4':break;
}
}
}