Error in Output !
This is a program for a quiz competition.
The program seems to run fine but when I try to display the result it displays junk. Please HELP !!
#include<iostream.h>
#include<fstream.h>
#include<string.h>
#include<stdio.h>
#include<stdlib.h>
int no=1;
class quizz
{
public:
char question[100];
char answer[10];
void get()
{
cout<<"Enter the question"<<endl;
gets(question);
cout<<"Enter the answer"<<endl;
gets(answer);
}
};
class participant
{
char name[10];
int sno;
float score;
public:
void add()
{
sno=0;
cout<<"Enter your name :"<<endl;
gets(name);
score=0;
}
void assign(int k)
{
sno=k;
}
void show()
{
cout<<sno<<" "<<name<<"\t"<<score<<endl;
}
void calc(float s)
{
score=s;
}
int retsno()
{
return sno;
}
float retscore()
{
return score;
}
char* retname()
{
return name;
}
};
void main()
{
system("cls");
char ch='Y'; int choice;
while(ch=='Y'||ch=='y')
{
cout<<"Press 1 to Enroll for quiz."<<endl;
cout<<"Press 2 to take up the quiz"<<endl;
cout<<"Press 3 to input a question into database"<<endl;
cout<<"Press 4 to display reults"<<endl;
cout<<"Press 5 to exit"<<endl;
cin>>choice;
switch(choice)
{
case 1:
{
participant p; fstream f;
f.open("participant.dat",ios::out|ios::ate|ios::binary);
p.add();p.assign(no); no++;
f.write((char*)&p,sizeof(p));
cout<<"Your are enrolled succesfully."<<endl;
cout<<"Your participant number is "<<p.retsno()<<endl;
f.close();
break;
}
case 2:
{
participant p,r;quizz q; char na[25];float s=0;
fstream f,f1;char ques[30],ans[10];int n,flag=0;
f.open("quiz.dat",ios::in|ios::binary);
f1.open("participant.dat",ios::in|ios::binary);
cout<<"Enter your participant number ! "; cin>>n;
cout<<"Enter your name ! "; gets(na);
while(!f.eof())
{
f1.read((char*)&p,sizeof(p));
if((strcmp(na,p.retname())==0)&&p.retsno()==n)
{
flag=1;
break;
}
}
f1.close();
if(flag==1)
{
cout<<"Quiz has begun."<<endl<<"1. For every correct answer you will get 4 marks"<<endl;
cout<<"2. For every incorrect answer you will lose 1 mark"<<endl;
cout<<"Please answer the following questions."<<endl;
for(int i=0;i<3;i++)
{
f.read((char*)&q,sizeof(q));
cout<<q.question<<endl;
gets(ans);
if(strcmp(q.answer,ans)==0)
s+=4;
else
s-=1;
}
f.close();
p.calc(s);
f1.open("participant.dat",ios::in|ios::out|ios::binary);
while(!f.eof())
{
f1.read((char*)&r,sizeof(r));
if((strcmp(r.retname(),p.retname())==0)&&r.retsno()==p.retsno())
{
f1.seekg(-sizeof(p),ios::cur);
f1.write((char*)&p,sizeof(p));
break;
}
}
}
f1.close();
break;
}
case 3:
{char ch;
do
{
fstream f;quizz q;
f.open("quiz.dat",ios::out|ios::ate|ios::binary);
q.get();
f.write((char*)&q,sizeof(q));
f.close();
cout<<"Do you want to input more questions ? (Y/N)";
cin>>ch;
}
while(ch=='y'||ch=='Y');
break;
}
case 4:
{
fstream f;participant o,m;float max=0;
f.open("particpant.dat",ios::in|ios::binary);
while(f.read((char*)&o,sizeof(o)))
{
o.show();
if(o.retscore()>max)
{
m=o;
max=o.retscore();
}
}
f.close();
cout<<"The winner of the quiz is..."<<endl;
m.show();
break;
}
case 5:
{
exit(0);
}
default:
break;
}
cout<<"Do you want to try again ? (Y/N)";
cin>>ch;
}
}
The program seems to run fine but when I try to display the result it displays junk. Please HELP !!
#include<iostream.h>
#include<fstream.h>
#include<string.h>
#include<stdio.h>
#include<stdlib.h>
int no=1;
class quizz
{
public:
char question[100];
char answer[10];
void get()
{
cout<<"Enter the question"<<endl;
gets(question);
cout<<"Enter the answer"<<endl;
gets(answer);
}
};
class participant
{
char name[10];
int sno;
float score;
public:
void add()
{
sno=0;
cout<<"Enter your name :"<<endl;
gets(name);
score=0;
}
void assign(int k)
{
sno=k;
}
void show()
{
cout<<sno<<" "<<name<<"\t"<<score<<endl;
}
void calc(float s)
{
score=s;
}
int retsno()
{
return sno;
}
float retscore()
{
return score;
}
char* retname()
{
return name;
}
};
void main()
{
system("cls");
char ch='Y'; int choice;
while(ch=='Y'||ch=='y')
{
cout<<"Press 1 to Enroll for quiz."<<endl;
cout<<"Press 2 to take up the quiz"<<endl;
cout<<"Press 3 to input a question into database"<<endl;
cout<<"Press 4 to display reults"<<endl;
cout<<"Press 5 to exit"<<endl;
cin>>choice;
switch(choice)
{
case 1:
{
participant p; fstream f;
f.open("participant.dat",ios::out|ios::ate|ios::binary);
p.add();p.assign(no); no++;
f.write((char*)&p,sizeof(p));
cout<<"Your are enrolled succesfully."<<endl;
cout<<"Your participant number is "<<p.retsno()<<endl;
f.close();
break;
}
case 2:
{
participant p,r;quizz q; char na[25];float s=0;
fstream f,f1;char ques[30],ans[10];int n,flag=0;
f.open("quiz.dat",ios::in|ios::binary);
f1.open("participant.dat",ios::in|ios::binary);
cout<<"Enter your participant number ! "; cin>>n;
cout<<"Enter your name ! "; gets(na);
while(!f.eof())
{
f1.read((char*)&p,sizeof(p));
if((strcmp(na,p.retname())==0)&&p.retsno()==n)
{
flag=1;
break;
}
}
f1.close();
if(flag==1)
{
cout<<"Quiz has begun."<<endl<<"1. For every correct answer you will get 4 marks"<<endl;
cout<<"2. For every incorrect answer you will lose 1 mark"<<endl;
cout<<"Please answer the following questions."<<endl;
for(int i=0;i<3;i++)
{
f.read((char*)&q,sizeof(q));
cout<<q.question<<endl;
gets(ans);
if(strcmp(q.answer,ans)==0)
s+=4;
else
s-=1;
}
f.close();
p.calc(s);
f1.open("participant.dat",ios::in|ios::out|ios::binary);
while(!f.eof())
{
f1.read((char*)&r,sizeof(r));
if((strcmp(r.retname(),p.retname())==0)&&r.retsno()==p.retsno())
{
f1.seekg(-sizeof(p),ios::cur);
f1.write((char*)&p,sizeof(p));
break;
}
}
}
f1.close();
break;
}
case 3:
{char ch;
do
{
fstream f;quizz q;
f.open("quiz.dat",ios::out|ios::ate|ios::binary);
q.get();
f.write((char*)&q,sizeof(q));
f.close();
cout<<"Do you want to input more questions ? (Y/N)";
cin>>ch;
}
while(ch=='y'||ch=='Y');
break;
}
case 4:
{
fstream f;participant o,m;float max=0;
f.open("particpant.dat",ios::in|ios::binary);
while(f.read((char*)&o,sizeof(o)))
{
o.show();
if(o.retscore()>max)
{
m=o;
max=o.retscore();
}
}
f.close();
cout<<"The winner of the quiz is..."<<endl;
m.show();
break;
}
case 5:
{
exit(0);
}
default:
break;
}
cout<<"Do you want to try again ? (Y/N)";
cin>>ch;
}
}
Next time, use the [code][/code] tags (the <> icon)
> The program seems to run fine but when I try to display the result it displays junk.
You need to say what combination of 1..5 menu options you chose, and what you typed in to create records.
You also need to delete any existing .dat files if you've been messing about with the layout of your structures.
Also, don't forget all your obsolescence problems!
http://www.cplusplus.com/forum/general/248648/
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> The program seems to run fine but when I try to display the result it displays junk.
You need to say what combination of 1..5 menu options you chose, and what you typed in to create records.
You also need to delete any existing .dat files if you've been messing about with the layout of your structures.
Also, don't forget all your obsolescence problems!
http://www.cplusplus.com/forum/general/248648/
> Also, don't forget all your obsolescence problems!
http://www.cplusplus.com/forum/general/248648/
Yea, i fixed those errors.
> You need to say what combination of 1..5 menu options you chose, and what you typed in to create records.
So i have copied the output screen of what typed to create records and the combination from the menu.
The final output where the winner of the quiz announced displays trash.
http://www.cplusplus.com/forum/general/248648/
Yea, i fixed those errors.
> You need to say what combination of 1..5 menu options you chose, and what you typed in to create records.
So i have copied the output screen of what typed to create records and the combination from the menu.
Press 1 to Enroll for quiz.
Press 2 to take up the quiz
Press 3 to input a question into database
Press 4 to display reults
Press 5 to exit
3
Enter the question
From which language is the word 'ketchup' derived ?
Enter the answer
chinese
Do you want to input more questions ? (Y/N)y
Enter the question
which is the country with the biggest population in Europe ?
Enter the answer
russia
Do you want to input more questions ? (Y/N)y
Enter the question
who portrayed Edward Scissorhands ?
Enter the answer
johnny depp
Do you want to input more questions ? (Y/N)n
Do you want to try again ? (Y/N)n
//I closed the program and ran it again.
Press 1 to Enroll for quiz.
Press 2 to take up the quiz
Press 3 to input a question into database
Press 4 to display reults
Press 5 to exit
1
Enter your name :
Jack
Your are enrolled succesfully.
Your participant number is 1
Do you want to try again ? (Y/N)n
//I closed the program and ran it again
Press 1 to Enroll for quiz.
Press 2 to take up the quiz
Press 3 to input a question into database
Press 4 to display reults
Press 5 to exit
2
Enter your participant number ! 1
Enter your name ! Jack
Quiz has begun.
1. For every correct answer you will get 4 marks
2. For every incorrect answer you will lose 1 mark
Please answer the following questions.
From which language is the word 'ketchup' derived ?
chinese
Which is the country with the biggest population in Europe ?
russia
Who portrayed Edward Scissorhands ?
johnny depp
Do you want to try again ? (Y/N)n
//I closed the program and ran it again
Press 1 to Enroll for quiz.
Press 2 to take up the quiz
Press 3 to input a question into database
Press 4 to display reults
Press 5 to exit
4
The winner of the quiz is...
8308 orhands ? 3.04788e+32
Do you want to try again ? (Y/N)n
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The final output where the winner of the quiz announced displays trash.
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Because the first thing you see is "The winner....", perhaps investigate why o.show() is never called.
Which in turn might explain why m = o; is never called.
Which might in turn explain why m.show() shows garbage.
Actually, the garbage thing would be resolved if your structs had a proper constructor to initialise the member variables to something you would recognise as "uninitialised".
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