Question

I’m a beginner C# programmer, and to improve my skills I decided to give Project Euler a try. The first problem on the site asks you to find the sum of all the multiples of 3 and 5 under 1000. Since I’m essentially doing the same thing twice, I made a method to multiply a base number incrementally, and add the sum of all the answers togethor.

public static int SumOfMultiplication(int Base, int limit)
    {
        bool Escape = false;
        for (int mult = 1; Escape == true; mult++)
        {
            int Number = 0;
            int iSum = 0;
            Number = Base * mult;
            if (Number > limit)
                return iSum;
            else
                iSum = iSum + Number;

        }

regardless of what I put in for both parameters, it ALWAYS returns zero. I’m 99% sure it has something to do with the scope of the variables, but I have no clue how to fix it. All help is appreciated.

Thanks in advance,

Sam

Answer 1

Your loop never actually executes:

bool Escape = false;
for (int mult = 1; Escape == true; mult++)

Escape is set to false initially, so the first test fails (Escape == true returns false) and the body of the loop is skipped.

The compiler would have told you if you were trying to access variables outside of their defined scope, so that’s not the problem. You are also missing a return statement, but that is probably a typo.

I would also note that your code never checks if the number to be added to the sum is actually a multiple of 3 or 5. There are other issues as well (for example, iSum is declared inside of the loop and initialized to 0 after each iteration), but I’ll let you work that one out since this is practice. The debugger is your friend in cases like these 🙂

EDIT: If you need help with the actual logic I’ll be happy to help, but I figure you want to work it out on your own if possible.