My practice

#include "pch.h"
#include <iostream>
#include <cmath>

using namespace std;
int main(){
    /*double nums[3]; ///1
    double bigest = 1;
    double sum = 0;
    for (int i = 0; i < (sizeof(nums) / sizeof(nums[0])); i++) {
        std::cin >> nums[i];
        if (nums[i] > bigest) bigest = nums[i];
        sum += nums[i];
    }
    std::cout << sum / bigest;*/

    /*double U, v;
    cin >> v;
    if (v < 1){
        U = atan(v) - exp(v);
    } else if (v > 1 && v <= 3 && v != 2){
        U = log10(v + cos(v));
    } else {
        cout << "v = 1 || v = 2 || v > 3";
        return 0 ;
    }
    cout << "U = " << U;*/

    /*int i, k, n; Исправить, кста\ добавить проверку нижней
    cout << "type i, k : ";
    cin >> i >> k;
    double sum = 0;
    for ( n = i ;  n <= k;  n++){
        double summ = n / (n*n+5*n+6.);
        if (summ == 0){
            cout << 0;
        }
        else
        {
            sum += summ;
        }

    }
    cout << "sum is : " << sum;*/

}