Question

Microsoft Visual Studios 2017

Write a C++ program that computes a student’s grade for an assignment as a percentage given the student’s score and total points. The final score must be rounded up to the nearest whole value using the ceil function in the <cmath> header file. You must also display the floating-point result up to 5 decimal places. The input to the program must come from a file containing a single line with the score and total separated by a space.

In addition, you must print to the console “Excellent” if the grade is greater than or equal to 90, “Well Done” if the grade is less than 90 and greater than or equal to 80, “Good” if the grade is less than 80 and greater than or equal to 70, “Need Improvement” if the grade is less than 70 and greater than or equal to 60, and “Fail” if the grade is less than 60.

Attempted sol'n:

// Header files section
#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <cmath>
using namespace std;

// start main function
int main()
{
   // variables declaration
   string fileName;
   string lastName;
   double score;
   double total;
   double grade;
   string description;

   // prompt the user to enter the input file name
   cout << "Enter the input file name: ";
   cin >> fileName;

   // open the input file
   ifstream infile;
   infile.open(fileName);
  
   // exit from the program if the input file does not open
   if (!infile)
   {
       cout << fileName << " file cannot be opened!" << endl;
       exit(1);
   }

   // repeat the loop for all students in the file
   infile >> lastName;
   while (infile)
   {
       infile >> score;
       infile >> total;

       // compute the grade
       grade = score / total * 100;

       // find the grade's description
       if (grade > 90)
           description = "Excellent";
       else if (grade > 80)
           description = "Well Done";
       else if (grade > 70)
           description = "Good";
       else if (grade >= 60)
           description = "Need Improvement";
       else
           description = "Fail";

       // display the result of each student
       cout << lastName << " " << setprecision(0) << fixed << round(grade) << "% " << setprecision(5) << fixed << (grade * 0.01) << " " << description << endl;

       infile >> lastName;
   }

   // close the input file
   infile.close();

   system("pause");
   return 0;
} // end of main function

Program runs, but can't get the input file name.

Answer 1

// Header files section
#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <cmath>
using namespace std;
// start main function
int main()
{
// variables declaration
string fileName;
string lastName;
double score;
double total;
double grade;
string description;
// prompt the user to enter the input file name
cout << "Enter the input file name: ";
cin >> fileName;
   // open the input file
ifstream infile;
infile.open(fileName.c_str()); //We need to use c_str() method to provide constructor of ifstream const char * (which is what the c_str() method provides.
  
// exit from the program if the input file does not open
if (!infile)
{
cout << fileName << " file cannot be opened!" << endl;
exit(1);
}
// repeat the loop for all students in the file
infile >> lastName;
while (infile)
{
infile >> score;
infile >> total;
// compute the grade
grade = score / total * 100;
// find the grade's description
if (grade > 90)
description = "Excellent";
else if (grade > 80)
description = "Well Done";
else if (grade > 70)
description = "Good";
else if (grade >= 60)
description = "Need Improvement";
else
description = "Fail";
// display the result of each student
cout << lastName << " " << setprecision(0) << fixed << round(grade) << "% " << setprecision(5) << fixed << (grade * 0.01) << " " << description << endl;
infile >> lastName;
}
// close the input file
infile.close();
system("pause");
return 0;
} // end of main function