C++ program: How you will fill in the fourth column with the grade averages by u

Question

C++ program: How you will fill in the fourth column with the grade averages by using two dimensional array? How to loop through array that holds the student names and letter grades only? Create an array 4x4 to handle student grades. Please output only the name of the student and letter grade to a file and to the console. Thanks.

Note: The names and letter grade should be a string.

StudentNames.txt

James

John

Jonas

Joel

StudentGrades.txt

100    87    72

73       65    45

100    45    70

48      80     89

Sample Output:

James             B

John               D

Jonas              C

Joel                 C

Explanation / Answer

#include<iostream>
#include<fstream>
#include<string>
#include<iomanip>
using namespace std;

const int MAX = 50;
// a function called GetData to read and store data into two arrays,
void GetData(ifstream& infile,string name[],int scores[][5],int& n)
{
n = 0;
int i=0;
int j=0;
while(!infile.eof())
{
infile >> name[i];
for(int j=0; j<5; j++)
infile >> scores[i][j];
i++;
}
n = i;
}

char determineGrade(double avg)
{
if(avg>=90 && avg<=100)
return 'A';
else if(avg>=80 && avg<=89)
return 'B';
if(avg>=70 && avg<=79)
return 'C';
if(avg>=60 && avg<=69)
return 'D';
if(avg>=50 && avg<=59)
return 'F';
}

// a function called Average that is used to calculate the average test score and grade,
void Average(int a[][5],char grade[],double avg[],int no_of_students)
{
for(int i=0; i<no_of_students; i++)
{
double sum =0;
for(int j=0; j<5; j++)
sum+= a[i][j];
avg[i] = sum/static_cast<double> (5);
grade[i] = determineGrade(avg[i]);
}
}

// function called PrintResults to output the results.
void PrintResults(string name[],double avg[],int scores[][5],char grade[],int n)
{
for(int i=0; i<n; i++){
cout << left << setw(10)<< name[i];
for(int k=0; k<5; k++)
cout << right << setw(8) << scores[i][k];
cout << endl;
}
cout << setw(8) <<"Average ";
for(int i=0; i<n; i++)
cout << setw(5) << avg[i];
cout << endl;
}

int main()
{
// a one-dimensional array to store the students names,
string name[MAX];
// a (parallel) two-dimensional array to store the test scores,
int scores[MAX][5];
// a parallel one-dimensional array to store grades.
char grade[MAX];
int no_of_students;
double avg[MAX];

ifstream infile("StudentData.txt");

if(!infile)
{
cout <<"unable to open file.so exiting from program" << endl;
return 0;
}

GetData(infile, name, scores, no_of_students);
infile.close();
Average(scores, grade, avg, no_of_students);
PrintResults(name,avg,scores,grade,no_of_students);

return 0;
}

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