Practice 2
1. Find the multiplication product of all numbers divisible by 3
starting from 3 to 100. You can use a 'WHILE' loop.
2. Write a program using a 'WHILE' loop to count from 10 to 0
inclusively
In the end print 'Let's Go!'
3. Write a program that does the following things:
a. Asks 7 numbers from a user
b. Prints total sum of user's numbers
c. Counts total amounts of positive and negative inputs, and inputs
equalled to zero. Use 'if', 'elif' and else' decision operators for this
task

Uses Crt;

Const
   N = 39;
Var
   X:array[1..N] of integer;
   i,j,k:integer;

Begin
Randomize;
ClrScr;
k:=0;
WriteLn('Исходный массив: ');
For i:= 1 to N do
    Begin
    X[i]:=random(53)-15;
    if X[i]<30 then
       Begin
       TextColor(12);
       k:=k+1;
       End
    else TextColor(7);
    Write(X[i],' ');
    End;
WriteLn;
WriteLn;
TextColor(7);
WriteLn('Числа, меня тридцати: ',k);
WriteLn;
WriteLn('Упорядоченный массив: ');
For i:= 1 to N do
    For j:= 1 to N-1 do
        if X[j]>X[j+1] then
           Begin
           k:=X[j+1];
           X[j+1]:=X[j];
           X[j]:=k;
           End;
k:=0;
For i:= 1 to N do
    Begin
    Write(X[i],' ');
    j:=X[i];
    While j div 10 <> 0 do
       j:=j div 10;
    if (j = 2)or(j = -2) then
       k:=k+1;
    End;
WriteLn;
WriteLn;
WriteLn('Числа, начинающиеся с двойки: ',k);
ReadLn;
End.

//PascalABC.NET версия 3.2, сборка 1389
//Если программа не запускается, то обновите версию
const
    n = 200;

var
    primes: array of integer;

begin
    primes := ArrGen(n, i -> i);
    
    for var i := 2 to round(sqrt(n)) do
    begin
        if not (primes.Contains(i)) then
            continue;
        var e := SeqWhile(i*i, x -> x + i, x -> x <= n);
        primes := primes.Except(e).ToArray;
    end;
    
    writeln('Простые числа < ', n, ':');
    writeln(primes);
    writeln;
    writeln('Время вычисления: ', Milliseconds / 1000);
end.