С++ программирование на С++

 #include <iostream> 
#include <ctime> 
#include <cstdlib> 
 
using namespace std; 
 
int main() 
{ 
 int n, n1, n2, i, sum; 
 double * A, sred; 
 
 do 
 { 
  cout << "n = "; 
  cin >> n; 
 }while(n < 2 || n > 20); 
 
 do 
 { 
  cout << "n1 = "; 
  cin >> n1; 
 }while(n1 < 1 || n1 >= n); 
 
 do 
 { 
  cout << "n2 = "; 
  cin >> n2; 
 }while(n2 <= n1 || n2 > n); 
 
 A = new double[n]; 
 
 sum = 0; 
 srand(time(nullptr)); 
 for(i = 0; i < n; i++) 
 { 
  A[i] = (rand() % 10001 - 5000) * 0.001; 
  sum += A[i]; 
  cout << A[i] << " "; 
 } 
 cout << endl << endl; 
 
 sred = static_cast<double>(sum) / static_cast<double>(n); 
 
 for(i = n1; i <= n2; i++) 
  if(A[i] < 0.0) 
   A[i] = sred; 
 
 for(i = 0; i < n; i++) 
  cout << A[i] << " "; 
 cout << endl; 
 
 if(A == (double*) nullptr) exit(1); 
 delete [] A; 
 A = (double*) nullptr; 
 
 return 0; 
}