Average score facing some technical issues - c

Question

I have followed everything in the book, yet my average score fails me, every single time. I have debugged my program multiple times, in vain.
My minimal executable code:
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>
#define MAX_TESTS 5
#define MAXQUESTION 10000
bool myread(const char * format, void * address) {
char buffer[1024];
fgets(buffer, sizeof buffer, stdin);
return sscanf(buffer, format, address) == 1;
}
struct struc {
int a;
int b;
int c;
int add;
int grade;
};
int sj(int n) {
int t;
t = rand() % n;
return t;
}
void ctm_i(struct struc * t) {
{
t -> a = sj(101);
t -> c = sj(4);
if (t -> c == 1) {
t -> b = sj(101 - (t -> a));
t -> add = (t -> a) + (t -> b);
} else {
t -> b = sj((t -> a) + 1);
t -> add = (t -> a) - (t -> b);
}
t -> grade = 0;
}
}
void tcm_i(struct struc * t, int n) {
int ad;
printf(" ***********************************************************************"
"*********\n");
printf(" ......................................................................."
".........\n");
printf(" Question %d\n\n", n + 1);
printf(" You have 3 attempts for this question\n\n");
if (t -> c == 1)
printf(" %d+%d= ", t -> a, t -> b);
else
printf(" %d-%d= ", t -> a, t -> b);
myread(" %d", & ad);
if (ad == t -> add)
{
t -> grade = 10;
printf(" You earned 10 marks\n\n");
} else {
printf("\n Incorrect, you have 2 attempts remaining\n\n");
printf(" ");
myread(" %d", & ad);
if (ad == t -> add)
{
t -> grade = 7;
printf(" You earned 7 marks\n\n");
} else {
printf("\n Incorrect, you have 1 attempt remaining\n\n");
printf(" ");
myread(" %d", & ad);
if (ad == t -> add)
{
t -> grade = 5;
printf(" You earned 5 marks\n\n");
} else {
t -> grade = 0;
printf("\n Failure, 0 mark\n\n");
printf("\n The correct answer is %d\n\n", t -> add);
}
}
}
printf(" ......................................................................."
".........\n");
printf(" ***********************************************************************"
"*********\n");
}
void quiz(char name[]) {
int rounds = 0;
int highest = 0;
int lowest = INT_MAX;
float allScore = 0;
float avg = 0.0;
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
}
allScore += g; //add current round's score to total
avg = allScore / rounds; //average of all rounds
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);
printf(" Average score: %f/100\n", avg);
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;
}
}
int main() {
char i1 = '1';
char name[25]; // ig;
printf("\n Welcome");
printf("\n");
while (i1 != 0) {
printf("\n");
//printf(" **********************Welcome %s! *********************\n", name);
printf(" ************************ Main Menu of Maths Quiz ***************************\n");
printf(" * 1.Enter Quiz *\n");
printf(" * 2.Quit *\n");
printf(" ****************************************************************************\n");
printf(" Please choose one from 1-2:\n");
printf(" ");
myread(" %c", & i1);
switch (i1) {
case '1':
printf("\n Enter Quiz:\n");
quiz(name); // calling quiz function defined in file "maincode.c"
break;
case '2':
printf(" Quit.\n\n");
}
}
return 0;
}
Hope that fulfilled the definition of an MRE.
So I have snipped off some bombastic lines, and the ones left are the important ones, I think.

Answer 1

The problem is in your function quiz, and in particular in the while (unsure) loop. In this loop, you add the most recent score to the running total:
allScore += g; //add current round's score to total
This should happen once per round played. But if the user inputs "S" or something invalid, your program sets
unsure = true;
which means the loop will run again, before the next round is played. It then adds the most recent score a second time to the grand total.
The most logical solution would be to move all the calculations of totals, maximum, minimum, average out of the while-loop. The loop serves a different purpose: it is for user interaction and reporting, not for processing results.

Answer 2

possible chance of multiple avg calculation for same round again. Keep flag to track accounting of score, so we will not do the same more than once till the game is not played again.
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>
#define MAX_TESTS 5
#define MAXQUESTION 10000
bool myread(const char * format, void * address) {
char buffer[1024];
fgets(buffer, sizeof buffer, stdin);
return sscanf(buffer, format, address) == 1;
}
struct struc {
int a;
int b;
int c;
int add;
int grade;
};
int sj(int n) {
int t;
t = rand() % n;
return t;
}
void ctm_i(struct struc * t) {
{
t -> a = sj(101);
t -> c = sj(4);
if (t -> c == 1) {
t -> b = sj(101 - (t -> a));
t -> add = (t -> a) + (t -> b);
} else {
t -> b = sj((t -> a) + 1);
t -> add = (t -> a) - (t -> b);
}
t -> grade = 0;
}
}
void tcm_i(struct struc * t, int n) {
int ad;
printf(" ***********************************************************************"
"*********\n");
printf(" ......................................................................."
".........\n");
printf(" Question %d\n\n", n + 1);
printf(" You have 3 attempts for this question\n\n");
if (t -> c == 1)
printf(" %d+%d= ", t -> a, t -> b);
else
printf(" %d-%d= ", t -> a, t -> b);
myread(" %d", & ad);
if (ad == t -> add)
{
t -> grade = 10;
printf(" You earned 10 marks\n\n");
} else {
printf("\n Incorrect, you have 2 attempts remaining\n\n");
printf(" ");
myread(" %d", & ad);
if (ad == t -> add)
{
t -> grade = 7;
printf(" You earned 7 marks\n\n");
} else {
printf("\n Incorrect, you have 1 attempt remaining\n\n");
printf(" ");
myread(" %d", & ad);
if (ad == t -> add)
{
t -> grade = 5;
printf(" You earned 5 marks\n\n");
} else {
t -> grade = 0;
printf("\n Failure, 0 mark\n\n");
printf("\n The correct answer is %d\n\n", t -> add);
}
}
}
printf(" ......................................................................."
".........\n");
printf(" ***********************************************************************"
"*********\n");
}
void quiz(char name[]) {
int rounds = 0;
int highest = 0;
int lowest = INT_MAX;
float allScore = 0;
float avg = 0.0;
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;
bool acct = false;
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 /////////////
if (false == acct) {
g = 0;
// calculate total score for current round
for (i = 0; i < MAX_TESTS; i++) {
g += test[i].grade; //add score of each question
}
allScore += g; //add current round's score to total
avg = allScore / rounds; //average of all rounds
if (g > highest) {
highest = g;
}
if (g < lowest) {
lowest = g;
}
acct = true;
}
if (showS &&(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);
printf(" Average score: %f/100\n", avg);
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;
}
}
int main() {
char i1 = '1';
char name[25]; // ig;
printf("\n Welcome");
printf("\n");
while (i1 != 0) {
printf("\n");
//printf(" **********************Welcome %s! *********************\n", name);
printf(" ************************ Main Menu of Maths Quiz ***************************\n");
printf(" * 1.Enter Quiz *\n");
printf(" * 2.Quit *\n");
printf(" ****************************************************************************\n");
printf(" Please choose one from 1-2:\n");
printf(" ");
myread(" %c", & i1);
switch (i1) {
case '1':
printf("\n Enter Quiz:\n");
quiz(name); // calling quiz function defined in file "maincode.c"
break;
case '2':
printf(" Quit.\n\n");
}
}
return 0;
}
Output:
Enter 'S' to show results
Enter 'P' to play another round
Enter 'R' to return to main menu
s
Round 2 score: 47/100
Highest score: 50/100
Lowest score : 47/100
Average score: 48.500000/100
****** Player: ******