В матрице 6 на 6 заменить четные элементы, стоящие выше и ниже главной диагонали нулями​

Program lol (input, output);
var a, n, b, i, p,s, m:integer;
c:real;
begin
read (n);
a:=n;
b:=0;
c:=0;
p:=1;
while a <> 0 do
begin
a:=a div 10;
b:=b+1;
end;
while b <> 0 do
begin
p:=1;
for m:=1 to b do
p:=p*10;
s:=(n mod p) div (p div 10);
c:=c+s;
end;
b:=b-1;
end;
writeln (c);
end.

program lol (input, output);
var I, a:integer;
begin
a:=0;
for I:=31 to 55 do
begin
if (i mod 2) <> 0 then
a:=a+I;
end;
writeln (a);
end.


var a, b, c, s, I:integer;
begin
read (a, b);
if a<b then
begin
c:=a;
a:=b;
b:=c;
end;
c:=a;
while c > 0 do
begin
while c >= b do
begin
c:=a-b;
if c > 0 then
s:=c;
a:=c;
end;
a:=b;
b:=c;
end;
writeln (s);
end.

program lol (input, output);
var m, n, prod: word;
begin
readln(m, n);
prod := m * n;
while m <> n do
begin
if m > n then
begin
m := m - n
end
else
begin
n := n - m
end
end;
writeln(prod div m)
end.

program lol (input, output);
var a, b, c, e:Integer;
d:real;
begin
read (a, b);
d:=a/b;
c:=trunc(d);
e:=a-(b*c);
writeln ('Частное: ',c);
writeln ('Остаток: ',e);
end.

#include <iostream>
#include <cmath>
using namespace std;
class Circle
{
private:
    double x;
    double y;
    double r;
public:
    Circle();
    Circle(double xCo, double yCo, double rad);
    double area();
    double centre_dist(Circle & c);
    bool istouch(Circle & c);
};

Circle::Circle()
{
    cout << "Enter x coord: ";
    cin >> x;
    cout << "Enter y coord: ";
    cin >> y;
    cout << "Enter radius: ";
    while (cin >> r && r < 0)
    {
        cout << "Radius can't be negative\n";
        cout << "Enter radius: ";
    }
}

Circle::Circle(double xCo, double yCo, double rad) : x(xCo), y(yCo), r(rad)
{
    if (r < 0)
    {
        cout << "Radius can't be negative\n";
        cout << "Radius set to 0\n";
        r = 0;
    }
}

double Circle::area()
{
    return 3.1415926 * r * r;
}

double Circle::centre_dist(Circle & c)
{
    return sqrt((x - c.x) * (x - c.x) + (y - c.y) * (y - c.y));
}

bool Circle::istouch(Circle & c)
{
    return (this->centre_dist(c) <= r + c.r) ? true : false;
}

int main()
{
    Circle c1;
    Circle c2(0, 0, 5);
    cout << "area of c2: " << c2.area() << endl;
    cout << "centre distance: " << c2.centre_dist(c1) << endl;
    cout << "is touch: ";
    c2.istouch(c1) ? cout << "yes" : cout << "no";
    cout << endl;
    return 0;
}