include

using namespace std;

int main() {
int arr[12] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12};
int sum = 0;

for(int i = 0; i < 12; i++) {
sum += arr[i];
}
float average = (float)sum / 12;
arr[4] = average;
cout << "Исходный массив:" << endl;
for(int i = 0; i < 12; i++) {
cout << arr[i] << " ";
}
cout << endl;
return 0;

}