File I/O assignment [closed] - c++

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I am working on an assignment, and the instruction is below:
This fifth assignment will allow you to better explore the concept of File I/O within the C++ programming language.
For this assignment, you are going to read-in (using C++ File I/O) the contents of a text file (.txt) and calculate the letter grade for a given student based upon weighted averages and write this out to a text file (.txt). We will use the weights as outlined in the Syllabus for this course: Assignments: 50%, Participation: 10%, Midterm Exam: 20%, Final Exam: 20%. Your program should read-in the grade category and then each of the respective scores separated/delimited by a comma.
Once you have finished reading the contents of the file you will need to invoke a function, calculateLetterGrade, that has a return type of void and two parameters: one of type double with By-Value semantics and the other of type char with By-Reference semantics. Your program should then write this calculated grade to another user specified text file (.txt) before terminating. You are expected to check to ensure that each respective file opens and that you properly close your file(s). The output file should have a score of 85.8 and letter grade B
Here is my code:
#include <iostream>
#include <fstream>
#include <string>
void calculateLetterGrade(double score, char &grade);
int main(){
std::string fileName("");
char grade;
double totalScore(0);
std::cout << "Welcome to the great Grade Calculator!" << std::endl;
std::cout << "Please enter the file you wish to open: ";
std::cin >> fileName;
// open file to read
std::ifstream file(fileName);
//display the file on the console
if(file.is_open())
{
std::cout << "Reading from file " << fileName << "...\n";
std::cout << "Here is your file " << std::endl;
while(std::getline(file, fileName))
{
std::cout << fileName << std::endl;
}
}
else
{
std::cout << "Unable to open file. " << std::endl;
}
// loop upto end of file
while(!file.eof())
{
// read type
std::string gradeCategory("");
file >> gradeCategory; //stream extraction
// assign the weight in each category
double weight(0);
if(gradeCategory == "Assignments")
{
weight = 0.5; //50%
}
else if(gradeCategory == "Participation")
{
weight = 0.1; //10%
}
else if(gradeCategory == "Midterm" || gradeCategory == "Final")
{
weight = 0.2; //20%
}
double total(0), count(0);
// read count of scores for type
file >> count;
// loop for count times
for(int i = 0; i < count; i++)
{
// read score and add to total
double score;
file >> score;
total = total+score;
}
// calculate average and add weighted score to totalScore
double average = total/count;
totalScore = totalScore+(average*weight);
}
// close file
file.close();
// call function to get grade
std::cout << "Calculating grades...\n";
calculateLetterGrade(totalScore,grade);
// read output filename and open it
std::cout << "Save To (Filename): ";
std::cin >> fileName;
std::ofstream fileForGrade(fileName);
// write score to file
fileForGrade << totalScore;
// write grade to file and then close file
fileForGrade << grade;
fileForGrade.close();
std::cout << "Score & Letter Grade written to file: " << fileName << std::endl;
std::cout << "Thank you for using my program, have a bless day!" << std::endl;
return 0;
}
// function to calculate grade by give score
void calculateLetterGrade(double score, char &grade){
// assign 'A' if score greater than or equal to 90
if(score>=90){
grade = 'A';
}
// assign 'B' if score greater than or equal to 80
else if(score>=80){
grade = 'B';
}
// assign 'C' if score greater than or equal to 70
else if(score>=70){
grade = 'C';
}
// assign 'D' if score greater than or equal to 60
else if(score>=60){
grade = 'D';
}
// assign 'F', means fail
else{
grade = 'F';
}
}
My code compiles, but the output file comes out to be 0 F. Can someone point out what I did wrong in the code?
UPDATE: here is my latest code:
#include <iostream>
#include <fstream>
#include <string>
#include <sstream>
void calculateLetterGrade(double score, char &grade);
int main(){
std::string fileName("");
char grade;
double totalScore(0);
std::cout << "Welcome to the great Grade Calculator!" << std::endl;
std::cout << "Please enter the file you wish to open: ";
std::cin >> fileName;
// open file to read
std::ifstream file(fileName);
//display the file on the console
if(file.is_open())
{
std::cout << "Reading from file " << fileName << "...\n";
std::cout << "Here is your file " << std::endl;
std::string line;
while(std::getline(file, line))
{
std::cout << line << std::endl;
std::istringstream iss(line);
std::string gradeCategory;
iss >> gradeCategory;
// assign the weight in each category
double weight(0);
if(gradeCategory == "Assignments")
{
weight = 0.5; //50%
}
else if(gradeCategory == "Participation")
{
weight = 0.1; //10%
}
else if(gradeCategory == "Midterm" || gradeCategory == "Final")
{
weight = 0.2; //20%
}
double total(0);
int count(0);
// read count of scores for type
iss >> count;
// loop for count times
for(int i = 0; i < count; ++i)
{
// read score and add to total
double score;
iss >> score;
total += score;
}
// calculate average and add weighted score to totalScore
double average = total/count;
totalScore = totalScore+(average*weight);
}
}
else
{
std::cout << "Unable to open file. " << std::endl;
}
// close file
file.close();
// call function to get grade
std::cout << "Calculating grades...\n";
calculateLetterGrade(totalScore,grade);
// read output filename and open it
std::cout << "Save To (Filename): ";
std::cin >> fileName;
std::ofstream fileForGrade(fileName);
// write score to file
fileForGrade << totalScore;
// write grade to file and then close file
fileForGrade << " " << grade;
fileForGrade.close();
std::cout << "Score & Letter Grade written to file: " << fileName << std::endl;
std::cout << "Thank you for using my program, have a bless day!" << std::endl;
return 0;
}
// function to calculate grade by give score
void calculateLetterGrade(double score, char &grade){
// assign 'A' if score greater than or equal to 90
if(score>=90){
grade = 'A';
}
// assign 'B' if score greater than or equal to 80
else if(score>=80){
grade = 'B';
}
// assign 'C' if score greater than or equal to 70
else if(score>=70){
grade = 'C';
}
// assign 'D' if score greater than or equal to 60
else if(score>=60){
grade = 'D';
}
// assign 'F', means fail
else{
grade = 'F';
}
}
And here is my input file named grade.txt:
Assignments
75,86,90,80,95,100
Participation
90
Midterm
75
Final
90

Answer 1

After the 1st while loop reads all of the file, file's position is at the end of the file. You need to call file.seekg(0) to reset the position back to the beginning of the file before you can read the contents again in the 2nd while loop.
std::ifstream file(fileName);
...
while(std::getline(file, fileName))
{
std::cout << fileName << std::endl;
}
file.seekg(0); // <-- ADD THIS!
...
That being said, consider combining the 2 loops. You can use std::istringstream to parse each line that is read.
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
...
std::ifstream file(fileName);
if (file.is_open())
{
...
std::string line;
while (std::getline(file, line))
{
std::cout << line << std::endl;
std::istringstream iss(line);
std::string gradeCategory;
iss >> gradeCategory;
...
int count = 0;
iss >> count;
double total = 0.0;
for (int i = 0; i < count; ++i)
{
double score;
iss >> score;
total += score;
}
...
}
}
else
{
std::cout << "Unable to open file. " << std::endl;
}
...
UPDATE: given that we can now see what you input file actually looks like, the code shown so far will not be able to read it correctly. You will have to make some additional logic changes to the reading loop, eg:
...
std::string line;
while (std::getline(file, line))
{
std::cout << line << std::endl;
// assign the weight in each category
std::string gradeCategory = line;
double weight = 0.0;
if (gradeCategory == "Assignments")
{
weight = 0.5; //50%
}
else if (gradeCategory == "Participation")
{
weight = 0.1; //10%
}
else if (gradeCategory == "Midterm" || gradeCategory == "Final")
{
weight = 0.2; //20%
}
// read scores and add to total
std::getline(file, line);
std::istringstream iss(line);
double score, total = 0.0;
int count = 0;
char comma;
while (iss >> score)
{
total += score;
++count;
iss >> comma;
}
if (count != 0)
{
// calculate average and add weighted score to totalScore
double average = total / count;
totalScore += (average * weight);
}
}
...
Demo