Faulty Average Score

[Eve Wein]

C program.

Problem: Faulty average score output.

My program gives faulty average score output, no matter how I debug it, it is still there, and it has become a pain in the ass lol.

void quiz(char name[]) {    int rounds = 0;    int highest = 0;    int lowest = INT_MAX;    float allScore = 0;    int avg = 0;    int i, j, g = 0;    struct struc test[MAX_TESTS];    srand((unsigned) time(NULL));    for (;;)    {        rounds++;        for (i = 0; i < MAX_TESTS; i++)    // generate all questions        {            ctm_i(&test[i]);            for (j = 0; j < i; j++)                if (test[i].a == test[j].a && test[i].b == test[j].b && test[i].c == test[j].c)                    //if question is already present                    ctm_i(&test[i]);    //then re-generate        }        printf("\n Are you ready? Press Enter key to continue. ");        myread("",NULL);        for (i = 1; i <= 5; i++)        {            printf(" *******************************************************************"                "**"                "***********\n");            printf(" ..................................................................."                ".."                "...........\n");        }        // Take quiz        for (i = 0; i < MAX_TESTS; i++)            tcm_i(&test[i], i);        printf(" End\n\n");        bool done = false;        bool unsure = true;        bool showS = true;        while (unsure)        {            unsure = false;            puts("\n");            if (showS)            {                puts(" Enter 'S' to show results");            }            puts(" Enter 'P' to play another round");            puts(" Enter 'R' to return to main menu");            char choice;            printf(" ");            myread("%c", &choice);            printf("\n");            if (choice == 'r' || choice == 'R')            {                done = true;            }            else            {                ///////////////////////// Changes    /////////////                g = 0;                // calculate total score for current round                for (i = 0; i < MAX_TESTS; i++)                {                    g += test[i].grade;    //add score of each question                } [b]                allScore += g;    //add current round's score to total[/b] [b]                avg = allScore / rounds;    //average of all rounds[/b]                if (g > highest)                {                    highest = g;                }                if (g < lowest)                {                    lowest = g;                }                if (choice == 'S' || choice == 's')                {                    showS = false;                    if (rounds == 1)                    {                        printf(" Final score: %d/100\n", g);    //display round score                        printf(" ******Player: %s ******\n", name);                    }                    else                    {                        printf(" Round %d score: %d/100\n", rounds, g);    //display round score                        printf(" Highest score: %d/100\n", highest);                        printf(" Lowest score: %d/100\n", lowest); [b]                        printf(" Average score: %d/100\n", avg);[/b]                        printf(" ******Player: %s ******\n", name);                    }                    unsure = true;                }                else if (choice == 'P' || choice == 'p')                {                         /// nothing to be done here                    //we will display next test                }                else                {                    puts(" Invalid input!");                    unsure = true;                }                ////////////////////////////////////            }        }        if (done)            break;    } }

Any help would be greatly appreciated.

[John Matthews]

Hi Eve - please could you post the rest of the code as well so I can compile it?

[Eve Wein]

John Matthews wrote:Hi Eve - please could you post the rest of the code as well so I can compile it?

Sure, John! I have tried sending the complete code, but received a "Post is too long, please shorten it. Alternatively you can buy some Pie from an upper menu to increase a post limit by 10000 characters per pie slice," warning. So I have posted my code to this link https://paste.ubuntu.com/p/7ZVmwnsX22/ feel free to check it out!

[John Matthews]

Thanks. I just added a printf() in the code where the average score is calculated and played one round - the printf() showed the average being updated correctly.

Then I was about to play my 2nd round - entered 'P' - and the printf() output again; my first round score had been added to allScore again, so it was no longer correct.

Try adding some printfs yourself - it's a simple way to debug code, doesn't need a fancy debugger.

[John Matthews]

...and the output shown in your original post confirms my printfs.

The output shows an (incorrect) average of 127. Well it looks like your first round score was 84, and second round was 87. (84 + 84 + 87) = 255, and (255 / 2) = 127.

[Eve Wein]

John Matthews wrote:Thanks. I just added a printf() in the code where the average score is calculated and played one round - the printf() showed the average being updated correctly.

Then I was about to play my 2nd round - entered 'P' - and the printf() output again; my first round score had been added to allScore again, so it was no longer correct.

Try adding some printfs yourself - it's a simple way to debug code, doesn't need a fancy debugger.

Thank you, may I ask which line of the code are you referring to?

[John Matthews]

Where the average is calculated, the ones you've helpfully marked [b] in your original post.

[Eve Wein]

John Matthews wrote:Where the average is calculated, the ones you've helpfully marked [b] in your original post.

Ah, I got it! Thank you.

[John Matthews]

Suggestions for improving/correcting print_positive_message():

#define ARRAY_SZ(a) (sizeof(a) / sizeof(a[0]))

static void print_positive_message(void)
{
    static const char *const positive_words[] =
    {
        "Bingo",
        "Great job",
        "Very good",
        "Brilliant",
        "That's correct",
        "You got it",
        "Bravo",
        "Awesome"
    };
    printf("\n %s!", positive_words[rand() % ARRAY_SZ(positive_words)]);
}

(correction) The function argument should be void; if left empty it means unspecified (although it would be correct in C++).

The function should be static - it is only used in this file.

The words array should be static, otherwise it is created on the stack every time the function executes.

The word array should be a (const) one dimensional array of (const) char pointers, not a 2 dimensional array of char. The compiler will store the strings in memory for you, only using as much memory as it needs to.

Use the ARRAY_SZ() macro to give the size of the array for the modulo calculation; avoids the use of 'magic numbers' and reduces maintenance overhead.

Move the '\n' and '!' into the printf() format string because they are common to all strings.