Function changes values when part of a for loop.

[Too Explosive]

I made a function to help solve problem 122 on Project Euler. When I run it on just a single number such as 35, it outputs 7; however, when the function is called in the for loop the return value changes to eight.

#include <iostream>
#include <vector>
#include <cmath>

int m(int);
bool isPrime(int);
std::vector<int> primes;

int main()
{
        //Prints 7
	std::cout << m(35) << '\n';

        //Will print 8 for 35
        for (int i = 1; i < 201; i++)
             std::cout << i << '\t' << m(i) << '\n';
	return 0;
}

int m(int k)
{
	if (k == 1)
		return 0;
	else if (k == 2)
		return 1;
	std::vector<int> prods;
	prods.push_back(1);
	int sum = 1, count = 0;
	if (k % 2 != 0)
	{
		count += 2;
		prods.push_back(2);
		prods.push_back(3);
		sum = 3;
		for (int i = k / 3; i > 3; i--)
		{
			if (k % i == 0 && isPrime(i))
			{
				while (sum < i)
				{
					sum += 2;
					count++;
					prods.push_back(sum);
				}
				break;
			}
		}
	}
	while (sum != k)
	{
		int index = prods.size() - 1;
		while (sum + prods.at(index) > k)
			index--;
		count++;
		sum += prods.at(index);	
		prods.push_back(sum);
	}
	return count;
}

bool isPrime(int x)
{
     for (int i = 2; i < sqrt(x); i++)
     {
          if (x % i == 0)
               return false;
     }
     return true;
}

[Repeater]

when part of the for loop the return value changes to eight.

That sentence doesn't make sense. There's something missing between "when part of the for loop" and "the return value changes to eight"

[lastchance]

7 and 7 on cpp.sh.

[Too Explosive]

Could it be a problem with my compiler than? I ran it on cpp.sh and did get seven both times but still get the eight on Visual Studio

[lastchance]

Copy it back into a clean project and try again.
cl.exe also gives 7 and 7, as does Microsoft Visual C++ through
https://rextester.com/BLPM87294

[Too Explosive]

I just deleted the project and then created a new one. I copied the code over yet the problem persists.

[lastchance]

Well, everything I try it on produces 7 and 7.

So, sorry, can't reproduce your findings anywhere.

[MikeyBoy]

Step through your code in a debugger. That will allow you to look at what the values of the variables are at each step of execution, which should help you identify why you're not getting the results you expect.