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I need some work to do to process my C++ knowledge. Can you guys help me on some kind of class or some kind of progressive learning that would ask something of me rather than just trying to pull programs to make out of the air? Please, I really want to learn and all I can do is a "Hello World" program and some simplistic cout cin if else programs.
Help would greatly be appreciated.
Well it depends how much you've covered so far but I saw the question below posted on here a few months back and thought it looked quite handy for rekindling my interest in C++. It might not be what your looking for but it seems to me like you could learn lots from it!
Quote:
Define a class called Animal with the following data attributes
Desc : array of 20 character
Height : float
Weight : float
Define a class Bird that inherits from Animal class above wit hthe following attributes:
Wingspan : float
Your program should be able to store up to 10 BirdRec records in an array called BirdsArray.
Your program should at least perform the below operations
- Add new birds records into BirdsArray
- Display all birds record
- Display the bird details with largeST winspan
- Display the bird details with lowest winspan
WOW that's so cool thank you for responding. Only can i talk to you about some of those things?
How about arrays (would I notate it like this?)
int (Variable/Array Name)[# of integers to be stored in this array (indexes)]
And what does Desc mean (describe maybe?).
I understand classes.
Yeah...floating point numbers can be any integer or real number (decimals).
Do I need to know inheritance for this?
Really sorry about the questions I just don't know all this stuff but I will learn it soon. Not asking for you to write this for me just need to know the functions, keywords and such.
Desc is probably a description, the animals name if you like. This is an inheritance question so there is lots of room to expand and practice with classes.
Animal class will be very general, it might include a function called eat( ) for example, which all Animals will do. Bird is a special type of Animal so adds further functionality and characterstics, perhaps fly( )???Code:class Animal
{
//animal attributes and functions.
};
class Bird : public Animal
{
//Bird attributes and functions.
};
Your best bet is to start with the Animal class only, and make sure you can create animals with a Desc a Weight and a Height that you are able to manipulate. Come back here when you get stuck :)
edit : Oh, and yes your array notation looks fine. Some quick examples:
Code:int ages[ 10 ];
char alphabet[ 26 ];
Day july[ 31 ];
Wait a minute...there's a C++ function called eat().....or can I just "make" or "name" a function how does that happen? Oh my god I thought I had to rely on keyword functions. Do you tell the function what to do (obviously if you create it)?
ok, take this example one step at a time. Look at class definitions, and try the first part about creating an Animal class. eat( ) isn't a standard C++ function, it is something you will have to create for yourself. Its is an action performed by any Animal, whereas fly is only performed by some animals.
Try taking away this example and creating an Animal class to use in a test program, then move onto bigger things :D
Code:#include <iostream.h>
int main() {
class Animal {
public:
float Height;
float Weight;
class Bird {
public:
float Wingspan;
}
That's what I've got so far. As for the array (that's supposed to be in the Bird structure), is that part of public, private, or none? And for the Bird class to inherit the Animal class...clueless. So how am I doing so far?
Try not to use old C style headers, change
to thisCode:iostream.h
As for your program looks good but i really dont think you can name somthing in a class public twice, try using private, or only having the publicCode:iostream
oh and the end of the class should be this
not what you have which is the brace without the colon. keep it up looking good, come back if you get stuck.Code:};
try sticking with the Animal class initially. Look at constructors, destructors, member functions, etc. Then move on to inheritance and playing with the Bird class. Your Animal class should look like this:
Look at creating and manipulating classes, try to find out why the data members should be private and what other functions you should add to the class.Code:class Animal
{
private:
float Height;
float Weight;
};
It'll be hard to tell you everything you need to learn classes. It took me quite a while to learn em. goto some sites such as
www.cplusplus.com
www.cplusabout.com
ww.functionx.com
There are tuts all around the internet. You will need to learn basic classes, functions, arrays, and maybe even pointers if you want to do advanced codes like that.
Yes you can make eat(). if you do some thing like..
You will have to read on functions to learn more about thisCode:int eat()
You can have as many public: tags in a class as you want.
[edit]
The link to www.cplusabout.com doesn't work.
[/edit]
www.cplus.about.com
my fault
Well I hope I'm set up right now. Please, if I'm horribly wrong, help. :DCode:#include <iostream.h>
int main() {
class Animal {
private:
int Animals[20];
protected:
float Height;
float Weight;
};
class Bird : protected Animal {
private:
float Wingspan;
int BirdsArray[10]
};
looks good so farCode:#include <iostream>
int main() { //where does main end???
class Animal {
private:
int Animals[20];
protected:
float Height;
float Weight;
};
class Bird : protected Animal {
private:
float Wingspan;
int BirdsArray[10] //semicolon
};
SCORE!!!.
The main doesn't end, I'm doing an assignment and before I code the operations i was just including the framework.
Now to actually make it do the operations.... Clueless. I'll post some ideas when I code some more.
Edit: Hmm. Well I'm starting to print some things to the user except that I don't know how to do a Yes/No user input prompt.
This is my current code.
How do I store the information into an array? Hmm..Code:#include <iostream.h>
int main() {
class Animal {
private:
int Animals[20];
protected:
float Height;
float Weight;
}; //end class Animal
class Bird : protected Animal {
private:
float Wingspan;
int BirdsArray[10];
}; //end class Bird
cout << "--------------Bird Array Program.-------------" << endl;
cout << "-Please type in your Bird to store in the program." << endl;
enum Bird {Height, Weight, Wingspan}
}//end Main
You should really be adding a little code and compiling, then adding a little code and compiling. If the compiling fails, you should not add any more code until you fix the errors. At the rate you are going you will have too many compile errors to fix before you ever attempt to compile your code. Just a suggestion.
I'm sorry to tell you this, but that is completely wrong. =\
You have to have at least some public objects in classes, not just private and protected, and cout isn't just going to cut it... here is a basic little class aplication that maybe you can learn and work with.
Note: I just made this up and didn't compile but it should work.Code:class Dog
{
public:
Dog();
~Dog();
int getage();
int getheight();
void setage(int age);
void setheight(int height);
void bark();
private:
int age;
int height;
};
Dog::Dog()
{
//constructor this is a basic example so it does nothing
}
~Dog::Dog()
{
//destructor this is a basic example so it does nothing
}
int Dog::GetAge() //basic class function
{
return age; //returns age
}
void Dog::SetAge(int age) //basic class function, returns nothing
{
age = 5;
}
void Dog::Bark()
{
cout << "Ruff Ruff" <<
}
int Dog::Getheight() //basic class function
{
return height; //returns height
}
void Dog::SetHeight(int height) //basic class function, returns nothing
{
height = 29;
}
main()
{
Dog Clifford;
Clifford.Setage(int age);
Clifford.SetHeight(int height);
Bark();
cout << "Clifford is << Clifford.GetAge << "years old/n" <<
cout << "Clifford is also" << Clifford.GetHeight << "inches tall/n" <<
return 0;
}
my fault I meant Clifford.Bark(); instead of just Bark();
I don't think this does what you think it does. As a matter of fact, a whole lot of that doesn't do what you think it does.Code:void Dog::SetHeight(int height) //basic class function, returns nothing
{
height = 29;
}
Quzah.
I'm really confused.
Renegade, it doesn't... you are assigning to a local variable (the function parameter), not the class member.
Okay, first of all, who's right. Second of all, can you help me? Why is mine so wrong?
nvm that was my fault, i just worded it terribly, i just get annoyed when some1 fixes what i say when i think it's right. But it was wrong, and I admit it. I knew what i was talking about but i worded it wrong and u guys prolly can't read minds. :(
Okay but is your code right? Or did you just word some things wrong? Ahh. :pQuote:
Originally Posted by Renegade
Renegade's code is not right. It has several things wrong with it, but those should probably be fixed in their own different thread.
blankstare77, your code has several things wrong with it, but most of all I think you are going about this task the wrong way. As I said you should make sure every little change you make compiles. So start with this:Make sure that compiles. Then maybe add an empty class:Code:int main()
{
}
Make sure that compiles. Continue adding one thing at a time and make sure it compiles. If it doesn't, chances are that whatever you just added was wrong. Then after you've got some actual code that compiles, you can ask if it is the right idea and nobody will have to waste time on the incorrect syntax and we can focus on the design and technique.Code:class Animal
{
};
int main()
{
}
The only bad thing about that is that I can't test class structures I can only test functions. People here say this is wrong:Quote:
Originally Posted by Daved
Really I just need to know how to store information into the array. I strongly believe that's right because I double-checked my inheritance, and why do people say that i can't have so many private variables? Why should I use public variables?Code:class Animal {
private:
int Animals[20];
protected:
float Height;
float Weight;
}; //end class Animal
class Bird : protected Animal {
private:
float Wingspan;
int BirdsArray[10];
}; //end class Bird
You can test classes just like you can test functions. If you don't know how to use classes to test them, then that will make it more difficult, but if that is the case then you should consult your book or tutorial instead of just trying things and asking for complete explanations.
You should use private member variables, that part is correct.
You need a way to access those private members, though. An easy way to do that is to provide get and set functions. For example, you could make a public function part of animal called getHeight that returns the height. You could make another public function setHeight that allows you to set the height. If you want to store information in the array, you will need a function that is part of the class that can add information to the array.
Of course, if your array is meant for the arrays mentioned in the problem at the top of this thread, then you aren't thinking of it correctly. The array inside the Animal class should be a character array to hold the description (Desc) of the animal. You have an int array. The array you put inside the Bird class is supposed to hold Birds. That array should be a variable inside your main function or some other function, it should not be part of Bird. Think about it, is a group of birds really a property of a bird?
You need code inside your main function that creates a Bird and sets its data. You need either a constructor or some other functions to set that data inside the Bird and inside the Animal base class. The inheritance should be public instead of protected. There are other issues. If you start over with new code and add one thing at a time, you will catch the compile errors, and there won't be so many issues to deal with at once.