Thread: what changes you would make?

Code:

// student_data_read_practice.cpp
// program which reads data of some students

#include <iostream>
#include <cstdlib>
#include <string>
#include <cstring>

using namespace std;

/* Move all this to a header file, using std:: as needed.*/
/////////////////////////////////////////////////////
struct Date {int d; string m; int y;}; //use longer variable names
////////////////////////////////////////////////////

/////////////////////////////////////////////////////
struct Student {int rollno; string sex; string name; float gpa; Date DOB;};
//don't use all caps for variable names 
//Make this into a class with print and read methods
/////////////////////////////////////////////////////

Student read();
void prnt(Student dummystud);
/*end of area to move*/

int main()
{
    Student stud[5];//Don't mix tabs and spaces for indination.

	for(int i=0; i<5; i++)
	{
	    cout << "enter student #" << (i+1) << "'s details below:-" << endl;
		stud[i] = read();
		prnt(stud[i]);
		cout << endl << endl;
	}

	system("pause");
	return 0;
}

//-----------------------------------------------
// Student read() definition

Student read()//I would make this a constructor for Student instead.
{
    Student stud; string name;

    cout << "enter name: "; getline(cin, name);
	cout << "enter roll number: "; cin >> stud.rollno;
	cout << "enter sex: "; cin >> stud.sex;
	cout << "enter date of birth (e.g. 01 Jan 2000) below:-" << endl;
	cout << "enter day: "; cin >> stud.DOB.d;
	cout << "enter month: "; cin >> stud.DOB.m;
	cout << "enter year: "; cin >> stud.DOB.y;
	cout << "enter GPA: "; cin >> stud.gpa;
	cin.ignore();

	return stud;
}

//-------------------------------------------------
// void prnt() definition

void prnt (const Student &dummystud)
{
    cout << "\n\n\n************************************\n\n\n";
	cout << "roll no.: " << dummystud.rollno << endl;
	cout << "name: " << dummystud.name << endl;
	cout << "sex: " << dummystud.sex << endl;
	cout << "date of birth: " << dummystud.DOB.d << "-" << dummystud.DOB.m
         << "-" << dummystud.DOB.y << endl;

	if (dummystud.gpa >= 3.5)
        cout << "grade: A" << endl;

	else if (dummystud.gpa >= 3.0)
        cout << "grade: B" << endl;

	else if (dummystud.gpa >= 2.0)
        cout << "grade: C" << endl;

    else
        cout << "Pass" << endl;

    cout << "\n\n\n************************************";
}

//----------------------------------------------------

Thanks a lot, Elysia, King Mir, whiteflags.

@Elysia: I haven't read anything about vectors so I don't know how to use them.

What's the benefit of const'ing the data type Student?

Code:

void prnt (const Student & dummystud)

Even without it the function won't accept anything else except Student data type structure. I understand the reason for passing arguments by reference.

@whiteflags: What you say is absolutely correct and valid. But I'm a beginner so I don't know how to really restrict the inputs. Obviously, it will make the code complex and longer.

@King Mir: How do you move that part of the code into a header? I didn't know there existed user created header files. Could you please tell me how to do this, if it's simple?

Thank you for the help.

Best wishes
Jackson

Originally Posted by jackson6612

What's the benefit of const'ing the data type Student?

Code:

void prnt (const Student & dummystud)

Even without it the function won't accept anything else except Student data type structure. I understand the reason for passing arguments by reference.

If you try to modify "dummystud" inside "prnt()", your compiler will complain. The same will happen if you call a "Student" member function in "prnt()" which is non-constant.

Originally Posted by jackson6612

@King Mir: How do you move that part of the code into a header? I didn't know there existed user created header files. Could you please tell me how to do this, if it's simple?

*) You create a new file as *.h or *.hpp or *.hh ( Stick with *.h )
*) You cut-paste your code there, making the necessary changes
*) Include your new header file in your project like this:

Code:

#include "myHeader.h"

Don't forget to wrap your header code in a preprocessor flag:

Code:

#ifndef __MY_HEADER_H__
#define __MY_HEADER_H__

// Your code goes here

#endif // __MY_HEADER_H__

Originally Posted by GReaper

Don't forget to wrap your header code in a preprocessor flag:

Code:

#ifndef __MY_HEADER_H__
#define __MY_HEADER_H__

// Your code goes here

#endif // __MY_HEADER_H__

That is not a "preprocessor flag". It is more usually described as an "include guard".

Also, in C++, never use identifiers (or macro names) that contain double underscores, or that begin with a single underscore. The standard reserves such identifiers for use by the implementation. That means, if you use them in your code (or header files) your code might break if the implementation (for example, in standard header files) uses the identifier you have.

Originally Posted by grumpy

That is not a "preprocessor flag". It is more usually described as an "include guard".

You say po-tay-to, I say po-tah-to.

Originally Posted by grumpy

That means, if you use them in your code (or header files) your code might break if the implementation (for example, in standard header files) uses the identifier you have.

Let's wish that never happens.

Originally Posted by GReaper

You say po-tay-to, I say po-tah-to.

Not at all. You gave wrong information, I corrected you. The term "preprocessor flag" has a completely different meaning from what you described.

Originally Posted by GReaper

Let's wish that never happens.

If wishes were fishes, the ocean would be full.