grading a quiz program

[owenkmc]

I have a homework assignment that I need to get done and here is the problem
This exercise is designed to introduce you to arrays and strings (i.e., arrays of characters) in c++.
suppose a class of tudents takes a 20-questions multiple choice exam; each question has five coices a-e onle one of which is correct and there are no blank responses. In the answers file there are a list of kids with their id numbers and 20 answers with no space between them. the program is to read through the file and produce the following

student id    num correct
430-52-6192            13
112-81-5225            19
etc
etc

number of students taking exam = 23

and should also output

question  a   b   c   d   e
1         5   1   13* 3   1
2         4   7*  1   7   4
3         etc etc etc etc etc

and so on where the correct answer has a * by it and there are twenty questions. This is what I have so far.

  #include <iostream>
#include <fstream>
using namespace std;
void main ()
{
	char key[21], id[12], responses[21];
int i
	ifstream testin, ansin;
	testin.open(“test.dat”)
ansin.open(“answers.dat”);
ansin>>key;
testin>>id>>responses[21];
	
	while(!fin.eof())
	{
		numstudents++;
		numcorrect=0;
		for(1=0; i<20; i++)
			if(responses[i]==key[i])
				numcorrect++;
			cout<<id<<numcorrect<<endl;
		
testin>>id>>responses;
	}
	
cout<<numstudents<<endl;
	

[owenkmc]

My bad this is the updated

  #include <iostream>
#include <fstream>
using namespace std;
void main ()
{
	char key[21], id[12], responses[21];
int i numstudents=0, numcorrect=0;
	ifstream testin, ansin;
	testin.open(“test.dat”)
ansin.open(“answers.dat”);
ansin>>key;
testin>>id>>responses[21];
	
	while(!fin.eof())
	{
		numstudents++;
		numcorrect=0;
		for(1=0; i<20; i++)
			if(responses[i]==key[i])
				numcorrect++;
			cout<<id<<numcorrect<<endl;
		
testin>>id>>responses;
	}
	
cout<<numstudents<<endl;
	

[LB]

Line 4: main must return an int
Line 7: Why are you declaring i here without a comma instead of declaring i on line 18 where you wrote 1 instead of i?

You're missing some closing braces. You should really fix your indentation.

[owenkmc]

sorry i missed that 1=0 that should be an i.

[code]
#include <iostream>
#include <fstream>
using namespace std;
void main ()
{
char key[21], id[12], responses[21];
int numstudents=0, numcorrect=0;
ifstream testin, ansin;
testin.open(“test.dat”)
ansin.open(“answers.dat”);
ansin>>key;
testin>>id>>responses[21];

while(!fin.eof())
{
numstudents++;
numcorrect=0;
for(int i=0; i<20; i++)
if(responses[i]==key[i])
numcorrect++;
cout<<id<<numcorrect<<endl;

testin>>id>>responses;
}

cout<<numstudents<<endl;
}
[\code]

why do I need to return an int on line 4 I am using a void function

[owenkmc]

#include <iostream>
#include <fstream>
using namespace std;
void main ()
{
char key[21], id[12], responses[21];
int numstudents=0, numcorrect=0;
ifstream testin, ansin;
testin.open(“test.dat”)
ansin.open(“answers.dat”);
ansin>>key;
testin>>id>>responses[21];

while(!fin.eof())
{
numstudents++;
numcorrect=0;
for(int i=0; i<20; i++)
if(responses[i]==key[i])
numcorrect++;
cout<<id<<numcorrect<<endl;

testin>>id>>responses;
}

cout<<numstudents<<endl;
}

[LB]

The main function is a special function, and one of its special characteristics is that it must have a return type of int. For the main function only, the return statement is optional.

[owenkmc]

so you are saying something like this?

#include <iostream>
#include <fstream>
using namespace std;
void main ()
{
	char key[21], id[12], responses[21];
int numstudents=0, numcorrect=0;
	ifstream testin, ansin;
	testin.open(“test.dat”)
ansin.open(“answers.dat”);
ansin>>key;
testin>>id>>responses[21];
	
	while(!fin.eof())
	{
		numstudents++;
		numcorrect=0;
		for(int i=0; i<20; i++)
			if(responses[i]==key[i])
				numcorrect++;
			cout<<id<<numcorrect<<endl;
		
testin>>id>>responses;
	}
	
cout<<numstudents<<endl;
int;
}

[LB]

I don't know what line 27 is for, we're talking about line 4 here.

https://en.wikipedia.org/w/index.php?title=Main_function&oldid=579287652#C_and_C.2B.2B

[owenkmc]

so

#include <iostream>
#include <fstream>
using namespace std;
int main (void);
{
	char key[21], id[12], responses[21];
int numstudents=0, numcorrect=0;
	ifstream testin, ansin;
	testin.open(“test.dat”)
ansin.open(“answers.dat”);
ansin>>key;
testin>>id>>responses[21];
	
	while(!fin.eof())
	{
		numstudents++;
		numcorrect=0;
		for(int i=0; i<20; i++)
			if(responses[i]==key[i])
				numcorrect++;
			cout<<id<<numcorrect<<endl;
		
testin>>id>>responses;
	}
	
cout<<numstudents<<endl;
}

[owenkmc]

It says expects a declaration on the int main (void);
{
the bracket says it expects a declaration but thats the only red line error that comes up

[LB]

You added a semicolon for some reason by mistake.

[owenkmc]

I'm now getting test.dat to have an error it says test is undifined and ansin.open says expected a ; lastly the !fin.eof says fin is undifined. Any ideas?

[owenkmc]

ok i put the ; on the test.dat") and now the ansin.open isnt errored but answers.dat") says answers is undifined any ideas?

[owenkmc]

ok now it just says the fin is undefined
here is what i have

#include <iostream>
#include <fstream>
using namespace std;
int main (void)
{
	char key[21], id[12], responses[21];
int numstudents=0, numcorrect=0;
	ifstream testin, ansin;
	testin.open("test.dat");
ansin.open("answers.dat");
ansin>>key;
testin>>id>>responses[21];
	
	while(!fin.eof())
	{
		numstudents++;
		numcorrect=0;
		for(int i=0; i<20; i++)
			if(responses[i]==key[i])
				numcorrect++;
			cout<<id<<numcorrect<<endl;
		
testin>>id>>responses;
	}
	
cout<<numstudents<<endl;
}

[LB]

The only input file streams you have are testin and ansin, so you need to use one of them instead of fin.

[owenkmc]

ok i got that fixed and now i have

#include <iostream>
#include <fstream>
using namespace std;
int main (void)
{
	char key[21], id[12], responses[21];
int numstudents=0, numcorrect=0;
	ifstream testin, ansin;
	testin.open("test.dat");
ansin.open("answers.dat");
ansin>>key[21];
testin>>id>>responses[21];
	
	while(!testin.eof())
	{
		numstudents++;
		numcorrect=0;
		for(int i=0; i<20; i++)
		
			if(responses[i]==key[i])
				numcorrect++;
			cout<<id<<numcorrect<<endl;
		
testin>>id>>responses;
	}
cout<<numstudents<<endl;
}

and its printing out

19
19
19
19
19
19
19
19
19
19
19
19
19
19
19
19
19

in and infinite loop... any suggestions on whats wrong