Thread: C Multiple Choice exam program

Hello, i needed to solve this question:

Write a program to grade a multiple choice exam. The exam has 20 questions, each answered with a little in the range of ‘a’ through ‘f’. The data are stored on a file (exams.dat) where the first line is the key consisting of a string of 20 characters. The remaining lines on the files are exam answers, and consist of a student ID number, a space, and a string of 20 characters. The program should read the key, then read each exam and output the ID number and score to file scores.dat. Erroneous input should result in an error message. For example, given the data:

abcdefabcdefabcdefab
1234567 abcdefabcdefabcdefab
9876543 abddefbbbdefcbcdefac
5554446 abcdefabcdefabcdef
4445556 abcdefabcdefabcdefabcd
3332221 abcdefghijklmnopqrst

The program should output on scores.dat:

1234567 20
9876543 15
5554446 Too few answers
4445556 Too many answers
3332221 Invalid answers

I came across this c++ code but am unsure on how to fully convert it to C. Please help

Code:

#include <string>#include <fstream>

using namespace std;

void WrongSize (ofstream&, int, string, string);

int main()
{
ifstream inData;
ofstream outData;
inData.open("exam.dat");
outData.open("scores.dat");

string key;
string student;
string answers;
int keylength;

inData >> key;
keylength = key.length();

do
{
inData >> student;
outData << student<< " ";
inData >> answers;
WrongSize (outData, keylength, answers, key);

}
while (!inData.eof());

return 0;
}


void WrongSize (ofstream& outData, int keylength, string answers, string key)
{

int grade = 0;
if (answers.length() < keylength)
{
outData << "Too few answers";
}
else if (answers.length() > keylength )
{
outData << "Too many answers";
}
else
{
bool check=false;

for (int count = 0; count < key.length(); count++)
{
if( answers[count] == key[count] )
grade++;
else if (answers[count] != 'a' && answers[count] != 'b' && answers[count] != 'c' && answers[count] != 'd' && answers[count] != 'e' && answers[count] != 'f')
check=true;
}

if (check==true)
{
outData << "Invalid Answer";
}
else
{
outData << grade;
}
}
outData << endl;
}