whats wrong with my function?

[joestevens232]

Ok everything is good...I read in all my grades into each of the different arrays that they need to go in. Now Im trying to write a function that takes the grades and computes the average on a hundred point scale...for example:
Student 1
7 quiz scores 9 9.33 8 10 5.5 8 10 ==> the 5.5 score should be dropped, returned value: 90.55
6 project scores 20 47.5 47 45 47.5 48 ==> returned value: 94.44
2 exam scores 83 87 ==> returned value: 85.00
14 lab scores 100 98 96 100 98 92 88 96 92 86 92 94 100 96 ==> returned value 94.86

heres what I got:

#include <cstdlib>
#include <iostream>
#include <string>
#include <vector>
#include <fstream>
using namespace std;
 
//Structure for holding all the grades                                          
struct MyGrades
{
    string student;
    float quizzes[7];
    float projects[6];
    float exams[2];
    float labs[14];
};
 
const int tot_quiz = 7;
const int tot_proj = 6;
const int tot_exam = 2;
const int tot_labs = 14;
const int tot_quiz_pts = 70;
const int tot_proj_pts = 300;
const int tot_exam_pts = 200;
const int tot_lab_pts = 150;
 
double ret_avg(float scores, int num_scores, int tot_pts);
 
int main()
{
    // outputting the correct format for all the averages to go                 
    cout << "No. -Name--     --Quiz-- -Project-  -Exam- -Lab- -Total-  Grade"
         << endl;
    cout << "--- ----------- -------- ---------- ------ ----- -------  -----"
         << endl;
    cout << endl;
 
    int student_number = 1; //counter for number of students                    
 
    ifstream in_file;
 
    MyGrades Grades; //declare an instance of a Grades struct                   
    in_file.open("grades.txt");  //opening the grades.txt file                  
 
    if(in_file.fail())  //if function to make sure the file opened              
    {
        cout << "Input file failed to open.\n";
        exit(1);
    }
 
    while (in_file >> Grades.student)  // reads in a string into a variable     
    {
        //reads in all the grades into each seperate array                      
        in_file >> Grades.quizzes[0] >> Grades.quizzes[1] >>
            Grades.quizzes[2] >> Grades.quizzes[3] >> Grades.quizzes[4] >>
            Grades.quizzes[5] >> Grades.quizzes[6] >> Grades.projects[0] >>
            Grades.projects[1] >> Grades.projects[2] >> Grades.projects[3] >>
            Grades.projects[4] >> Grades.projects[5] >> Grades.exams[0] >>
            Grades.exams[1] >> Grades.labs[0] >> Grades.labs[1] >>
            Grades.labs[2] >> Grades.labs[3] >> Grades.labs[4] >>
            Grades.labs[5] >> Grades.labs[6] >> Grades.labs[7] >>
            Grades.labs[8] >> Grades.labs[9] >> Grades.labs[10] >>
            Grades.labs[11] >> Grades.labs[12] >> Grades.labs[13];
 
        cout << " " << student_number << ".  " << Grades.student << "       "<<\
 ret_avg(Grades.quizzes, tot_quiz, tot_quiz_pts) << endl;
 
 
 
        student_number++;
    }
 
}
 
double ret_avg(float* scores, int num_scores, int tot_pts)
{
    double sum = 0;
    double avg = 0;
    for (int i = 0; i < num_scores; i++)
    {
        scores[i] += sum;
    }
    avg = sum / tot_pts;
    return (avg * 100);
}
 

heres the error message i get when i run it:
In function `int main()':
grader.cpp:71: error: cannot convert `float*' to `float' for argument `1' to `double ret_avg(float, int, int)'

and heres the output when run without calling the function in the cout

No. -Name--     --Quiz-- -Project-  -Exam- -Lab- -Total-  Grade
--- ----------- -------- ---------- ------ ----- -------  -----
 
 1.  Smith       
 2.  Jones       
 

I just want to know what's wrong with this function becuse I thought it would work perfectly but I guess I got something wrong in their. Also if anyone has any suggestions on how Im going to write a function to drop the lowest quiz from the quiz array and then run it in my ret_avg array to get the average of it on a scale of 100. Any help will be great!!!

[joestevens232]

Okay I just tried something else but its outputting a zero when i call it and print it out...i get a 0 under --Quiz--
here it is:...i donno which is closer...my 1st func or this one.

    while (in_file >> Grades.student)  // reads in a string into a variable     
    {
        //reads in all the grades into each seperate array                      
        in_file >> Grades.quizzes[0] >> Grades.quizzes[1] >>
            Grades.quizzes[2] >> Grades.quizzes[3] >> Grades.quizzes[4] >>
            Grades.quizzes[5] >> Grades.quizzes[6] >> Grades.projects[0] >>
            Grades.projects[1] >> Grades.projects[2] >> Grades.projects[3] >>
            Grades.projects[4] >> Grades.projects[5] >> Grades.exams[0] >>
            Grades.exams[1] >> Grades.labs[0] >> Grades.labs[1] >>
            Grades.labs[2] >> Grades.labs[3] >> Grades.labs[4] >>
            Grades.labs[5] >> Grades.labs[6] >> Grades.labs[7] >>
            Grades.labs[8] >> Grades.labs[9] >> Grades.labs[10] >>
            Grades.labs[11] >> Grades.labs[12] >> Grades.labs[13];
 
        ret_avg(Grades, tot_quiz, tot_quiz_pts, average);
        cout << " " << student_number << ".  " << Grades.student << "       "<<\
 average <<  endl;
 
 
 
        student_number++;
    }
 
}
 
double ret_avg(MyGrades& data, int num_scores, int tot_pts, double avg)
{
    double sum = 0;
    avg = 0;
    for (int i = 0; i < num_scores; i++)
    {
        data.quizzes[i] += sum;
    }
    avg = sum / tot_pts;
    return (avg * 100);
}
 

[weaknessforcats]

Your function prototype says:

double ret_avg(float scores, int num_scores, int tot_pts);
 

but you function says:

double ret_avg(float* scores, int num_scores, int tot_pts)
etc...
 

Fix your prototype.

[joestevens232]

ya disregard that part....i have it fixed in my program...I was just tryin stuff and I must of accidentally posted that version. something else is wrong with it.

[joestevens232]

heres what i currently have in my code: the function is just printing out a 0 for the quizzes for both students.

const int tot_quiz = 7;
const int tot_proj = 6;
const int tot_exam = 2;
const int tot_labs = 14;
const int tot_quiz_pts = 70;
const int tot_proj_pts = 300;
const int tot_exam_pts = 200;
const int tot_lab_pts = 150;
 
double ret_avg(float scores[], int num_scores, int tot_pts, double avg);
 
int main()
{
    // outputting the correct format for all the averages to go                 
    cout << "No. -Name--     --Quiz-- -Project-  -Exam- -Lab- -Total-  Grade"
         << endl;
    cout << "--- ----------- -------- ---------- ------ ----- -------  -----"
         << endl;
    cout << endl;
 
    double average = 0;
    int student_number = 1; //counter for number of students                    
 
    float exams[2];
    float labs[14];
};
 
const int tot_quiz = 7;
const int tot_proj = 6;
const int tot_exam = 2;
const int tot_labs = 14;
const int tot_quiz_pts = 70;
const int tot_proj_pts = 300;
const int tot_exam_pts = 200;
const int tot_lab_pts = 150;
 
double ret_avg(float scores[], int num_scores, int tot_pts, double avg);
 
int main()
{
    // outputting the correct format for all the averages to go                 
    cout << "No. -Name--     --Quiz-- -Project-  -Exam- -Lab- -Total-  Grade"
         << endl;
    cout << "--- ----------- -------- ---------- ------ ----- -------  -----"
         << endl;
    cout << endl;
 
    double average = 0;
    int student_number = 1; //counter for number of students                    
 
 
    ifstream in_file;
 
    MyGrades Grades; //declare an instance of a Grades struct                   
    in_file.open("grades.txt");  //opening the grades.txt file                  
 
    if(in_file.fail())  //if function to make sure the file opened              
    {
        cout << "Input file failed to open.\n";
        exit(1);
    }
 
    while (in_file >> Grades.student)  // reads in a string into a variable     
    {
        //reads in all the grades into each seperate array                      
        in_file >> Grades.quizzes[0] >> Grades.quizzes[1] >>
            Grades.quizzes[2] >> Grades.quizzes[3] >> Grades.quizzes[4] >>
            Grades.quizzes[5] >> Grades.quizzes[6] >> Grades.projects[0] >>
            Grades.projects[1] >> Grades.projects[2] >> Grades.projects[3] >>
            Grades.projects[4] >> Grades.projects[5] >> Grades.exams[0] >>
            Grades.exams[1] >> Grades.labs[0] >> Grades.labs[1] >>
            Grades.labs[2] >> Grades.labs[3] >> Grades.labs[4] >>
            Grades.labs[5] >> Grades.labs[6] >> Grades.labs[7] >>
            Grades.labs[8] >> Grades.labs[9] >> Grades.labs[10] >>
            Grades.labs[11] >> Grades.labs[12] >> Grades.labs[13];
 
        ret_avg(Grades.quizzes, tot_quiz, tot_quiz_pts, average);
        cout << " " << student_number << ".  " << Grades.student << "       "<<\
 average <<  endl;
 
 
 
        student_number++;
    }
 
}
 
double ret_avg(float scores[], int num_scores, int tot_pts, double avg)
{
    double sum = 0;
    avg = 0;
    for (int i = 0; i < num_scores; i++)
    {
        scores[i] += sum;
    }
    avg = sum / tot_pts;
    return (avg * 100);
}
 

[joestevens232]

ok i got it to work with :

double ret_avg(float scores[], int num_scores, int tot_pts)
{
    double sum = 0;
    double avg = 0;
    avg = 0;
    for (int i = 0; i < num_scores; i++)
    {
        sum = scores[i] + sum;
    }
    avg = sum / tot_pts;
    avg = avg * 100;
    return (avg);
}
 

but my output is 85.4714 for the first student and
75 for the second.....how do i get it to be 85.47 and 75.00 i tried using all floats and all doubles in the function. any suggestions?

[weaknessforcats]

but my output is 85.4714 for the first student and
75 for the second.....how do i get it to be 85.47 and 75.00 i tried using all floats and all doubles in the function. any suggestions?

Use a manipulator. Check out setprecision, setfill and width member functions of cout.

[joestevens232]

got it...thank you!!!

[joestevens232]

any ideas on how i can drop one of those quizzes or even just make the lowest score in the array a zero would work for me. any suggestions?

[weaknessforcats]

Just loop though the array comparing each element to a test minimum. Start wioth 0 and compare array[0] to array[i]. If array[i] is less than array[0], then i is your new minimum. When you get to the end of the array, you can use the i to set array[i] to any value you want.

For a truly variable array, you need to use a vector.