3 Задачки решить на с++

2)

#include <valarray>
#include <iostream>
#include <random>
using namespace std;
int main() {
uniform_int_distribution<> uid(10, 99);
mt19937 gen{ random_device()() };
valarray<int> box(10);
for (auto& x : box) x = uid(gen);
for (auto x : box) cout << x << ' ';
puts("");
const auto avg = double(box.sum()) / box.size();
cout.setf(ios::fixed);
cout.precision(1U);
cout << "Average: " << avg << '\n';
}

3)

#include <valarray>
#include <iostream>
#include <random>
using namespace std;
int main() {
uniform_int_distribution<> uid(10, 99);
mt19937 gen{ random_device()() };
valarray<int> box(10);
for (auto& x : box) x = uid(gen);
for (auto x : box) cout << x << ' ';
puts("");
cout << "Min: " << box.min() << '\n';
cout << "Max: " << box.max() << '\n';
}

1) что за "пары элементов", непонятно
2)
#include "ctime"
#include "cstdlib"
#include "iostream"
#include "algorithm"
using namespace std;
int main(){
int a[10]; srand(time(NULL));
for(int &i:a)cout<<(i=rand()%198-99)<<' '; cout<< endl;
cout<<"average="<< accumulate(a,a+10,0)/10.<< endl;}
3)
#include "ctime"
#include "cstdlib"
#include "iostream"
#include "algorithm"
using namespace std;
int main(){
const int n=20; int a[n]; srand(time(NULL));
for(int &i:a)cout<<(i=rand()%198-99)<<' '; cout<< endl;
cout<<"min="<<*min_element(a,a+n)<<", max="<<*max_element(a,a+n)<< endl;}

1)
#include < iostream >
#include < vector >
#include < algorithm >
using namespace std;
int main()
{
vector < int > prep;
srand(time(NULL));
int mas[7][7];
for (int i = 0; i < 49; i++) *(mas[0] + i) = rand() % 21;
for (int i = 0; i < 7; i++) {
for (int j = 0; j < 7; j++) cout << mas[i][j] << "\t";
cout << endl;
}
for (int i = 1; i < 7; i++)
for (int j = 0; j < i; j++) prep.push_back(mas[i][j]);
sort(prep.begin(), prep.end());
int count = 0;
for (int i = 1; i < prep.size(); i++) if (prep[i] == prep[i - 1]) {
count++; cout << "pair: " << prep[i] << " " << prep[i - 1] << endl;
i++;
}
cout <<"\n\n" << count;
}

Никогда не пишите так)