Verified answer

#include <iostream>

#include <cstdlib>

#include <ctime>

using namespace std;

int main() {

setlocale(0, "");

srand(time(0));

int arr[5][7];

float average = 0;

int counter = 0;

for(int i = 0; i<5; ++i) {

 for(int j = 0; j<7; ++j) {

  arr[i][j]=rand();

  cout << arr[i][j] << " ";

  if(j==6) {

   cout << endl;

  }

  if(arr[i][j]>=0) {

   average+=arr[i][j];

   ++counter;

  }

 }

}

cout << "Средний: " << average/counter;

system("pause");

}