Массивы в С++

#include <iostream>
#include <ctime>

using namespace std;

int main()
{
const int n = 12;
srand(time(NULL));
int a[n];
for(int x = 0; x < n; x++)
{
a[x] = rand() % (2*n);
cout << a[x] << ' ';
}
cout << endl << endl;
int max = a[0] + a[n-1];
for(int x = 1; x < n/2; x++)
if(a[x] + a[n-1-x] > max)
max = a[x] + a[n-1-x];

cout << max << endl;

return 0;
}

#include <iostream>
#include <random>
#include <set>
using namespace std;
unsigned integer(const char* msg) {
auto value = 0U;
while (!value || value & 1) {
cout << msg;
cin >> value;
cin.ignore(cin.rdbuf()->in_avail());
}
return value;
}
long long max(int* seq, const size_t len) {
set<long long, greater<>> box;
for (auto i = 0U, j = len - 1; i < j; ++i, --j) {
box.insert(long long(seq[i]) + seq[j]);
}
return *box.begin();
}
void test_1() {
int seq[] = { 23, 14, 57, 48, 69, 35, 41, 87, 62, 14, 33, 64 };
for (auto item : seq) cout << item << ' ';
puts("");
auto res = max(seq, size(seq));
cout << "max: " << res << '\n';
}
void test_2(const size_t len) {
auto seq = new int[len];
cout << "Elements: ";
for (auto i = 0U; i < len; ++i) cin >> seq[i];
auto res = max(seq, len);
cout << "max: " << res << '\n';
delete[] seq;
}
void test_3(int* seq, const size_t len) {
uniform_int_distribution<> uid(10, 99);
mt19937 gen{ random_device()() };
for (auto i = 0U; i < len; ++i) {
seq[i] = uid(gen);
cout << seq[i] << ' ';
}
puts("");
auto res = max(seq, len);
cout << "max: " << res << '\n';
}
int main() {
test_1();
auto len = integer("Length: ");
test_2(len);
auto seq = new int[len];
test_3(seq, len);
delete[] seq;
system("pause > nul");
}