when file couldn't be opened in c++, I want it to end the program, and not output more stuff!
my code:
#include<iostream>
#include <fstream>
#include<stdlib.h>
using namespace std;
// Function to accept a file names from the user and read file contents
// First Parameter: Student Answer file
// Second Parameter: Correct Answer file
// Third Parameter: Character type array to store student answers
// Fourth Parameter: Character type array to store correct answers
void readFile(string fileStuAns, string fileCorrAnswer, char sAns[], char cAns[])
{
// Initialize the line counter to zero
int counter = 0;
// Creates ifstream class objects
ifstream inSFile, inCFile;
// Opens the file for reading data from text file student answer
inSFile.open (fileStuAns.c_str());
// Opens the file for reading data from text file for correct answer
inCFile.open (fileCorrAnswer.c_str());
// Checks if student answer file can be opened or not
if(inSFile.fail())
{
// Displays error message
cout<<"File "<<"\""<<fileStuAns<<"\""<< " could not be opened"<<endl;
return;
}// End of if condition
// Checks if file can be opened or not
if(inCFile.fail())
{
// Displays error message
cout<<"File "<<"\""<<fileCorrAnswer<<"\""<< " could not be opened";
return;
}// End of if condition
// Loops till end of the student answer file
while(!inSFile.eof())
{
// Reads data from file and stores student answer character array's counter index position
inSFile>>sAns[counter];
// Increase the current line counter by one
counter++;
}// End of while
//Close student answer file
inSFile.close();
// Reset the counter to zero
counter = 0;
// Loops till end of correct answer the file
while(!inCFile.eof())
{
// Reads data from file and stores correct answer character array's counter index position
inCFile>>cAns[counter];
// Increase the current line counter by one
counter++;
}// End of while
// Close correct answer file
inCFile.close();
}// End of function
// Displays the student result
// First Parameter: Character type array contains student answers
// Second Parameter: Character type array contains correct answers
void resultSheet(char sAns[], char cAns[])
{
// Displays student answers
}// End of function
// Function to write data to file entered by the user
// First Parameter: Invalid Answer file
// Second Parameter: Character type array contains student answers
// Third Parameter: Character type array contains correct answers
void writeTextFile(string fileInAnschar, char sAns[], char cAns[])
{
// To store number of lines
int cA, iA;
cA = iA = 0;
// ofstream class object created
ofstream outFile;
// Opens the file for writing onto a text file
outFile.open(fileInAnschar.c_str());
// Checks if file can be opened or not
if(outFile.fail())
{
// Displays error message
cout<<"\n Error: Unable to open "<<fileInAnschar;
return;
}// End of if condition
// Loops till 20 times for 20 questions
for(int c = 0; c < 20; c++)
{
// If student answers current index position value is not equals to correct answer's current index position
if(sAns[c] != cAns[c])
{
// Writes the result to the file
outFile<<"Question "<<(c + 1)<<" has incorrect answer "<<"'"<<sAns[c]<<"'" <<", the correct answer is "<<"'"<<cAns[c]<<"'"<<endl;
// Displays the result
cout<<"Question "<<(c+1)<<" has incorrect answer "<<"'"<<sAns[c]<<"'"<<", the correct answer is "<<"'"<<cAns[c]<<"'"<<endl;
// Increase the counter by one
iA++;
}// End of if condition
}// End of for loop
// Calculates number of correct answers
cA = 20 - iA;
// Calculates the average
double percent = cA / 20;
// Checks if the average is greater than or equals 70
if(iA <= 6)
{
// Displays the result
cout<<iA<<" questions were missed"<<endl;
cout<<"The student passed"<<endl;
}// End of if condition
// Otherwise fail
else
{
cout<<iA<<" questions were missed"<<endl;
cout<<"The student failed"<<endl;
}// End of else
//Close file
outFile.close();
}//End of function
// main function definition
int main()
{
// Character array to store student answers
char studentAnswer[21];
// Character array to store correct answers
char correctAnswer[21];
// To store the file name
string fileNameStu, fileNameCorr;
// Accepts the file name to read
cin>>fileNameStu;
cin>>fileNameCorr;
// Calls the file to read student answer and correct answer and stores it in respective arrays
readFile(fileNameStu, fileNameCorr, studentAnswer, correctAnswer);
// Calls the function to display student answer and correct answer
resultSheet(studentAnswer, correctAnswer);
// Accepts the file name to write invalid answers
cin>>fileNameStu;
// Calls the function to write invalid answers
writeTextFile(fileNameStu, studentAnswer, correctAnswer);
}// End of main function
My output:
File "invalidfile.txt" could not be opened
b"Question 1 has incorrect answer '\xf0', the correct answer is '\x00'\nQuestion 2 has incorrect answer ';', the correct answer is '\x00'\nQuestion 3 has incorrect answer '\xae', the correct answer is '\x00'\nQuestion 4 has incorrect answer '\xa7', the correct answer is '\x00'\nQuestion 5 has incorrect answer '\xff', the correct answer is '\x00'\nQuestion 6 has incorrect answer '\x7f', the correct answer is '\x00'\n"Question 9 has incorrect answer 'T', the correct answer is ''
Question 10 has incorrect answer '', the correct answer is ''
Question 11 has incorrect answer '@', the correct answer is ''
Question 17 has incorrect answer '', the correct answer is 'p'
Question 18 has incorrect answer '', the correct answer is ''
Question 19 has incorrect answer '', the correct answer is '@'
12 questions were missed
The student failed
Output should be:
File "invalidfile.txt" could not be opened
Attached picture of output:
