无法弄清楚为什么我的变量不断恢复为零

Question

I am working on a project for school that is a console dice game. A problem that I have is that when I try to get the dice to score themselves the score variable always reverts to zero instead of what it should be. I may just be completely overlooking something simple as I am new to C++, but maybe y'all can help.

Here is my code for the scoring method:

void FindScoreNumbers()
{
    int scoreDie[6];
    int score = 0;
    bool isScoring = false;
    int flushCounter1 = 0;
    int flushCounter2 = 0;
    int flushCounter3 = 0;
    int flushCounter4 = 0;
    int flushCounter5 = 0;
    int flushCounter6 = 0;

    scoreDie[0] = castDie[0];
    scoreDie[1] = castDie[1];
    scoreDie[2] = castDie[2];
    scoreDie[3] = castDie[3];
    scoreDie[4] = castDie[4];
    scoreDie[5] = castDie[5];


    for (unsigned int i = 0; i < 6; ++i)
    {
        if (scoreDie[i] == 1)
        {
            score + 100;
            flushCounter1++;
            isScoring = true;

            if (flushCounter1 >= 3)
            {
                score + 800;
                isScoring = true;

            }
        }

        if (scoreDie[i] == 2)
        {
            flushCounter2++;
            if (flushCounter2 >= 3)
            {
                score + 200;
                isScoring = true;

            }
        }

        if (scoreDie[i] == 3)
        {
            flushCounter3++;
            if (flushCounter3 >= 3)
            {
                score + 300;
                isScoring = true;

            }
        }

        if (scoreDie[i] == 4)
        {
            flushCounter4++;
            if (flushCounter4 >= 3)
            {
                score + 300;
                isScoring = true;

            }
        }

        if (scoreDie[i] == 5)
        {
            score + 50;
            flushCounter5++;
            isScoring = true;

            if (flushCounter5 >= 3)
            {
                score + 400;
                isScoring = true;

            }
        }

        if (scoreDie[i] == 6)
        {
            flushCounter6++;
            if (flushCounter6 >= 3)
            {
                score + 600;
                isScoring = true;

            }
        }
    }

    if (isScoring = true)
    {
        std::cout << score << std::endl;    
    }
    else
    {
        std::cout << "FARKLE! You didn't roll any scoring die." << std::endl;
    }

}

I'm sorry if this isn't formatted properly this is my first question here. By the way, castDie[6] is the array of rolled die from a different bit of code. I also know that it returns the score

Answer 1

score + 800; should be score = score + 800; (same for all the others).

You can also shortcut with score += 800;

Answer 2

It should be:

score += 100;

This is shorthand for:

score = score + 100;