2 codes, same objective

[cibide]

Guys, why do this 2 codes give me different asnswers?

  #include <iostream>

using namespace std;

int main()
{
	int SumUp = 0;

	int nX3CMax = 333;
	for (int nX3 = 3 , nCountX3 = 0; nCountX3 <= nX3CMax; ++nCountX3)
		SumUp += (nX3 * nCountX3);

	int nX5CMax = 199;
	for (int nX5 = 5 , nCountX5 = 0; nCountX5 <= nX5CMax; ++nCountX5)
		SumUp += (nX5 * nCountX5);

	cout << SumUp << endl;
	system("pause");
	return 0;
}

  #include <iostream>

using namespace std;

int main()
{
	int SumUp = 0;

	for ( int iii = 1 ; iii < 1000 ; iii++)
		{	
			if ((iii % 3) == 0 || (iii % 5) == 0 )
				SumUp += iii;
		}

	cout << SumUp << endl;
	system("pause");
	return 0;
}

[2UD8vCM9]

I think the reason that it is not functioning like you expect is because there are numbers divisible by both 5 and 3 (for example: 15)

In the second code, you would only add this once, while in the first code, you're adding this twice.

Also please don't post such unclear code with no explanation on what it should even be doing. Your variable names are awful.

[MiiNiPaa]

Because they are doing different things.

Here is code which does same thing as first:

#include <iostream>

using namespace std;

int main()
{
    int SumUp = 0;

    for ( int iii = 1 ; iii < 1000 ; iii++) {
        if ((iii % 3) == 0)
            SumUp += iii;
        if ((iii % 5) == 0)
            SumUp += iii;
    }

    cout << SumUp << endl;
    system("pause");
}

[cibide]

You are both right... ty... and sorry for variables names, I will do better next time.