Final project error

[KevinRohdzz]

Hello, i got this error "clrscr undeclared" on all of my functions, but my friend who helped me with it looked at the code and said there was nothing wrong with it.



#include<conio.h>
#include<stdio.h>
#include<process.h>
#include<fstream.h>
#include<iomanip.h>


class student
{
int rollno;
char name[50];
int p_marks,c_marks,m_marks,e_marks,cs_marks;
float per;
char grade;
int std;
void calculate()
{
per=(p_marks+c_marks+m_marks+e_marks+cs_marks)/5.0;
if(per>=60)
grade='A';
else if(per>=50 && per<60)
grade='B';
else if(per>=33 && per<50)
grade='C';
else
grade='F';
}
public:
void getdata()
{
cout<<"\nEnter The roll number of student ";
cin>>rollno;
cout<<"\n\nEnter The Name of student ";
gets(name);
cout<<"\nEnter The marks in physics out of 100 : ";
cin>>p_marks;
cout<<"\nEnter The marks in chemistry out of 100 : ";
cin>>c_marks;
cout<<"\nEnter The marks in maths out of 100 : ";
cin>>m_marks;
cout<<"\nEnter The marks in english out of 100 : ";
cin>>e_marks;
cout<<"\nEnter The marks in computer science out of 100 : ";
cin>>cs_marks;
calculate();
}

void showdata()
{
cout<<"\nRoll number of student : "<<rollno;
cout<<"\nName of student : "<<name;
cout<<"\nMarks in Physics : "<<p_marks;
cout<<"\nMarks in Chemistry : "<<c_marks;
cout<<"\nMarks in Maths : "<<m_marks;
cout<<"\nMarks in English : "<<e_marks;
cout<<"\nMarks in Computer Science :"<<cs_marks;
cout<<"\nPercentage of student is :"<<setprecision(2)<<per;
cout<<"\nGrade of student is :"<<grade;
}

void show_tabular()
{
cout<<rollno<<setw(12)<<name<<setw(10)<<p_marks<<setw(3)<<c_marks<<setw(3)<<m_marks<<setw(3)<<e_marks<<setw(3)<<cs_marks<<setw(6)<<setprecision(3)<<per<<" "<<grade<<endl;
}

int retrollno()
{
return rollno;
}

}; //class ends here




fstream fp;
student st;


{
fp.open("student.dat",ios::out|ios::app);
st.getdata();
fp.write((char*)&st,sizeof(student));
fp.close();
cout<<"\n\nstudent record Has Been Created ";
getch();
}



void display_all()
{
clrscr();
cout<<"\n\n\n\t\tDISPLAY ALL RECORD !!!\n\n";
fp.open("student.dat",ios::in);
while(fp.read((char*)&st,sizeof(student)))
{
st.showdata();
cout<<"\n\n====================================\n";
getch();
}
fp.close();
getch();
}



void display_sp(int n)
{
int flag=0;
fp.open("student.dat",ios::in);
while(fp.read((char*)&st,sizeof(student)))
{
if(st.retrollno()==n)
{
clrscr();
st.showdata();
flag=1;
}
}
fp.close();
if(flag==0)
cout<<"\n\nrecord not exist";
getch();
}




void modify_student()
{
int no,found=0;
clrscr();
cout<<"\n\n\tTo Modify ";
cout<<"\n\n\tPlease Enter The roll number of student";
cin>>no;
fp.open("student.dat",ios::in|ios::out);
while(fp.read((char*)&st,sizeof(student)) && found==0)
{
if(st.retrollno()==no)
{
st.showdata();
cout<<"\nPlease Enter The New Details of student"<<endl;
st.getdata();
int pos=-1*sizeof(st);
fp.seekp(pos,ios::cur);
fp.write((char*)&st,sizeof(student));
cout<<"\n\n\t Record Updated";
found=1;
}
}
fp.close();
if(found==0)
cout<<"\n\n Record Not Found ";
getch();
}




void delete_student()
{
int no;
clrscr();
cout<<"\n\n\n\tDelete Record";
cout<<"\n\nPlease Enter The roll number of student You Want To Delete";
cin>>no;
fp.open("student.dat",ios::in|ios::out);
fstream fp2;
fp2.open("Temp.dat",ios::out);
fp.seekg(0,ios::beg);
while(fp.read((char*)&st,sizeof(student)))
{
if(st.retrollno()!=no)
{
fp2.write((char*)&st,sizeof(student));
}
}
fp2.close();
fp.close();
remove("student.dat");
rename("Temp.dat","student.dat");
cout<<"\n\n\tRecord Deleted ..";
getch();
}



void class_result()
{
clrscr();
fp.open("student.dat",ios::in);
if(!fp)
{
cout<<"ERROR!!! FILE COULD NOT BE OPEN\n\n\n Go To Entry Menu to create File";
cout<<"\n\n\n Program is closing ....";
getch();
exit(0);
}

cout<<"\n\n\t\tALL STUDENTS RESULT \n\n";
cout<<"====================================================\n";
cout<<"Roll No. Name P C M E CS %age Grade\n";
cout<<"====================================================\n";

while(fp.read((char*)&st,sizeof(student)))
{
st.show_tabular();
}
fp.close();
getch();
}





void result()
{
int ans,rno;
char ch;
clrscr();
cout<<"\n\n\nRESULT MENU";
cout<<"\n\n\n1. Class Result\n\n2. Student Report Card\n\n3.Back to Main Menu";
cout<<"\n\n\nEnter Choice (1/2)? ";
cin>>ans;
switch(ans)
{
case 1 :
class_result();
break;
case 2 :
{
do
{
clrscr();
char ans;
cout<<"\n\nEnter Roll Number Of Student : ";
cin>>rno;
display_sp(rno);
cout<<"\n\nDo you want to See More Result (y/n)?";
cin>>ans;
}
while(ans=='y'||ans=='Y');

break;
}
case 3:
break;
default:
cout<<"\a";
}
}



void intro()
{
clrscr();
gotoxy(35,11);
cout<<"STUDENT";
gotoxy(33,14);
cout<<"REPORT CARD";
gotoxy(35,17);
cout<<"PROJECT";
cout<<"\n\nMADE BY : Code With C";
cout<<"\n\nCONTACT : codewithc.com";
getch();

}




void entry_menu()
{
clrscr();
char ch2;
cout<<"\n\n\n\tENTRY MENU";
cout<<"\n\n\t1.CREATE STUDENT RECORD";
cout<<"\n\n\t2.DISPLAY ALL STUDENTS RECORDS";
cout<<"\n\n\t3.SEARCH STUDENT RECORD ";
cout<<"\n\n\t4.MODIFY STUDENT RECORD";
cout<<"\n\n\t5.DELETE STUDENT RECORD";
cout<<"\n\n\t6.BACK TO MAIN MENU";
cout<<"\n\n\tPlease Enter Your Choice (1-6) ";
ch2=getche();
switch(ch2)
{
case '1':
clrscr();
write_student();
break;
case '2':
display_all();
break;
case '3':
int num;
clrscr();
cout<<"\n\n\tPlease Enter The roll number ";
cin>>num;
display_sp(num);
break;
case '4':
modify_student();
break;
case '5':
delete_student();
break;
case '6':
break;
default:
cout<<"\a";
entry_menu();
}
}




void main()
{
char ch;
intro();
do
{
clrscr();
cout<<"\n\n\n\tMAIN MENU";
cout<<"\n\n\t01. RESULT MENU";
cout<<"\n\n\t02. ENTRY/EDIT MENU";
cout<<"\n\n\t03. EXIT";
cout<<"\n\n\tPlease Select Your Option (1-3) ";
ch=getche();
switch(ch)
{
case '1':
clrscr();
result();
break;
case '2':
entry_menu();
break;
case '3':
exit(0);
default :
cout<<"\a";
}
}
while(ch!='3');
}

[Moschops]

Setting aside the fact that you appear to be writing a horrible mishmash of C and C++ in the year 1990, which is something very wrong indeed (I'm afraid your friend is not a good source of information on C++), this would indicate that the non-standard header you're using, conio.h , doesn't contain a function named clsclr. Since conio.h is non-standard, there could be anything in there.

Open it up, see if the function exists. Maybe it's using namespaces. Could be anything; I dread to think what kind of tools you're using.

Then, if you don't have a time-machine in which to travel back to the mid-nineties so you can deploy your C++ code there, you should learn C++ from after the year 1998, and switch to using tools from this century.

[MikeyBoy]

@KevinRohdzz

Was your friend able to demonstrate exactly where clrscr is declared?

[dhayden]

Moschops, which standard tool do you suggest for clearing the screen? As far as I know, that's an OS-specific operation and C++ doesn't define any.

KevinRohdzz are you getting the error when compiling the code or when it links? If it's during the link phase then there is probably a library that you aren't liking against. Check your documentation for clrscr() to see what must be linked.

[Moschops]

Moschops, which standard tool do you suggest for clearing the screen?

I recommend coding to the C++11 standard. The code above is from before the 1998 standard, implying heavily that the tools being used are about 20 years old. Sad times.

We've got an article on clearing the screen: http://www.cplusplus.com/articles/4z18T05o/

Personally, I recommend that when that level of control is needed, one bites the bullet and either switches to a proper terminal library, or to graphics.