What happens inside the FOR loop?

Question

C++ / C#

Hello. The code is not mine, I'm trying to understand what's going on in the loop.
The program is designed to fulfill the condition

Given a natural number n and integers (m1...mn) . After each even member of the sequence with an odd number preceding the first member with the value max(m1...mn) , insert the value max(m1...mn).

The code itself:

#include <iostream>
#include <cstdlib>
using namespace std;
#define n 30
 
int main(){
    int mas[n];
    int max = -9999;
    int pos = 0;
    cout<<"In: ";
    for(int i = 0; i < n; i++){
        mas[i] = rand()%105 - 5;
        cout<<mas[i]<<" ";
        if(max < mas[i]){
            max = mas[i];
            pos = i;
        }
    }
    cout<<endl<<"Max = "<<max<<endl<<"Out ";
    for(int i = 0; i < n; i++){
        cout<<mas[i]<<" ";
                if(i < pos){
        if((i % 2 != 0) && (mas[i] % 2 == 0))
            cout<<max<<" ";
                }
    }
return 0;
}

Difficulties arise when trying to understand what is happening in the cycle, this line
for(int i = 0; i < n; i++)
is clear, but what happens further behind it is like a fog. It is also not clear why int max = -9999, because there is no word about it in the condition. Don't throw your slippers too hard, please, I've only been learning C++ for 2-3 weeks. I don't quite understand everything yet. Thanks in advance.

Answer 1

1) int max = -9999- initial initialization of the variable (with the hope that this is the maximum minimum value)
2) mas[i] = rand()%105 - 5;- assigning a random value to the cell with index i in the mas array
3) cout<<mas[i]<<" ";- displaying the value of cell i from the mas array to the console
4)

if(max < mas[i]){
            max = mas[i];
            pos = i;
        }

- checking if the current element of the array mas is greater than the value of the variable max, then we write the values ​​of cell i of the array mas to the variable max and store the index of cell i in the variable pos.
5) cout<<mas[i]<<" ";- displaying the i value of the mas array cell.
6) if(i < pos){}- if i is less than the position index of the maximum element
7)

if((i % 2 != 0) && (mas[i] % 2 == 0))
            cout<<max<<" ";
                }

- if the current index i is odd ( i % 2 != 0) AND ( &&) the element of the array mas with index i has an even value ( mas[i] % 2 == 0) , then output the maximum value to the console ( cout<<max<<" ";)

Answer 2

mas[i] = rand()%105 - 5; // записываем в ячейку массива случайное число диапазоне от 0 до 99
cout<<mas[i]<<" "; // выводим это число на консоль
if(max < mas[i]){   // ищем максимальное значение (max) и его индекс (pos) 
    max = mas[i];
    pos = i;
}

cout<<mas[i]<<" ";  // выводим значение текущей ячейки
if(i < pos){        // для всех элементов, предшествующих максимальному
    if((i % 2 != 0) && (mas[i] % 2 == 0))  // если номер нечетный и значение чётное
            cout<<max<<" ";   // выводим значение максимального элемента
}

I would not make such a decision. Instead of inserting into an array, it simply prints the number to the console.

why int max = -9999

So that before passing through the loop, the value of the current maximum (with which the numbers are compared) is guaranteed to be less than any number. Also govnokod, in such cases it is better to use INT_MIN.