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Vi3tboi911

Newbie C++ Help

212 posts in this topic

I'm gonna start teaching myself PHP/C/C++ soon and this thread is surely going to help me, but I'm a fair bit older than alot of the people in this thread looking to get into it too (20 as of last month) and I currently really only know HTML well. I was wondering, how long did it take some of you to learn C/C++/PHP to a somewhat decent level from scratch?

I'm curious how much time I might need to invest into learning. :)

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Dont know if its any use, or if its been found before, but IM not looking through 11 pages to see.

<link snipped--copyright infringement>

ITs the whole The

C+ +

Programming

Language

Third Edition

Bjarne Stroustrup

In PDF format XD.

Im using it atm.

Edited by John S.

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I thought I might add my input into this.

To get a good grounding on programming in general this book is a must read. It's a very tiny handbook as well, created by the founders of the C Programming Language.

Kernighan and Richie - The C Programming Language

It's aptly named as it is a no non-sense approach and tells very well how to make data structures, functions, arrays, and the basic functions of C. Though it took me a while to get my mind around a lot of the stuff written in the book. It all made picture perfect sense. It is a very System Engineering esque approach to programming, and they include the source code for the functions such as fgets, printf, and scanf.

I am learning C++ now, then moving onto C# after (After all, it is an exact copy of Java - Remade to have Microsoft brand on it).Another book was Data Structures and Algorithms with a picture of a waterfall on the front page, but that's for more advanced projects like Hash Tables, and AVL Trees.[That book got me full marks for my First Year University project].

I'm gonna start teaching myself PHP/C/C++ soon and this thread is surely going to help me, but I'm a fair bit older than alot of the people in this thread looking to get into it too (20 as of last month) and I currently really only know HTML well. I was wondering, how long did it take some of you to learn C/C++/PHP to a somewhat decent level from scratch?I'm curious how much time I might need to invest into learning. :)

From the start? Took me a 6 months to a year to get used to C Programming. Far from being a master - Haven't put the effort to become one.I guess you could say I am lost for inspiration to code. Don't know what to code.

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I'm not sure if this has been addressed, but if it has, feel free to delete this post.

Sometimes a newcomer in C++ can't figure out why after using something like cin >> value, something like cin.get(), which is supposed to wait for data to be entered, doesn't block input (doesn't wait for input) like it is supposed to. The answer is due to the fact that the input buffer that cin uses ends up not accepting the newline character that the Enter key uses when inputting data into variables. For example:

#include <iostream>


using namespace std;


int main () {

	int x = 40;


	cout << "Enter an integer: ";

	cin >> x;

	cout << x << endl << endl;


	cout << "Press Enter to exit..." << endl;

	cout << cin.bad() << cin.eof() << cin.fail() << endl;

	//cin.clear();

	//cin.sync();

	cin.get();

}

In that simple program, the cin.get() appears to be ignored. The same thing happens with variables of type bool, char, int, float, double, etc. There is a way around this problem, however. Just uncomment the commented lines in the above program and behold the difference! The first commented line clears the error bits, which is necessary because if they are not cleared then the cin.get() will notice the error from the previous read operation and will refuse to try doing an unsafe read. The second syncs the input buffer with the input stream, effectively discarding whatever extra characters are left in the input buffer.

Also note that this happens when doing the same thing with a string variable (an instance of the C++ string class, not a character array). However, it has a much safer solution - getline(cin, string_variable) instead of cin >> string_variable. It works by doing the same thing, except it discards the newline character. You can test this by using cout << string_variable.length() << endl; after using getline() and verifying that the number of characters you typed is the same as the string's length.

It is common for this same thing to happen in C with things like getchar() and scanf. C does not have any way to flush the input buffer, however. To accomplish this same thing, you might use something like while (getchar() != '\n');, or if you have a really crazy C compiler you could use while (getchar() != '\n') { continue; }, though I've never run into this type of thing personally.

I hope this helps people in the future!

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How different is C# from C++? I'm a beginner to programming, and want to go into C#, but I'm wondering if it'd be best if I learnt C++ first...
They just happen to have the same letter 'C'.

They are 2 completely different languages. C# is basically VB.NET (the functions are common, the same .NET framework) with a Java/C++ syntax and some of its features are taken from both Java and C++. C# for example can inherit from a class, not multiple like in C++ but you can have reference variables like in C++ but with a different syntax though.

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noob question.... why the below declaration is not good?

#include <iostream>

#include <string>


using namespace std;


class Str {

	public:

		Str(string *s) {

			this->x=s;

		};

		string getStr() {

			return this->x;

		}

	private:

		string x;

};


int main() {


	Str d = new Str("BOO");



	cout << d.getStr() << endl;

	return 0;

}

and how would a valid code look like :) ty in advance

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#include <iostream>
#include <string>

using namespace std;

class Str
{
public:
Str(string s)
{
x=s;
}

string getStr()
{
return x;
}
private:
string x;
};

int main() {

Str* d = new Str("BOO");


cout << d->getStr() << endl;
return 0;
}[/codebox]

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Str(string *s) {

			this->x=s;

		};
The problem is the fact that you are passing a pointer to a string, but you're trying to assign the pointer to the string. If that sounded confusing, it is -- pointers can be extremely confusing at times. You would need to dereference the pointer. I recommend the following, though Seismo's solution works just as well:
Str(string const& s) { //pass it by reference

			x=s;

		};
However, if you have your heart set on using a pointer, here is the corrected code:
Str(string *s) {

			x=*s;

		};

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Hello,

I have to write a simple program in c++ too count words, but i have some problems getting words from cin. If someone cam help me pls with some code it would be nice ;) I attached my work ;) ty ;)

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Hello,

I have to write a simple program in c++ too count words, but i have some problems getting words from cin. If someone cam help me pls with some code it would be nice ;) I attached my work ;) ty ;)

solved, i wrote a getword funtion ;)

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I have to say, if anyone is really serious about getting into some C or C++ I would seriously consider installing a free operating system such as GNU/Linux or FreeBSD. Once you get really in to it you will want to look at some advanced code for examples... and what better code to look at than the very software you are using! And what better way to learn than to hack it to pieces! Plus GCC is great :D

And for C++, one you have your head around the syntax, pointers, templates etc. I thoroughly recommend this book: The C++ Standard Library by Nicolai M. Josuttis: http://www.amazon.co.uk/C-Standard-Library...553&sr=11-1 Great read, great reference and good way to learn how to use templates and generic programming.

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ANyone know how to add color to c programming?> I want to change the font color and background color

That's quite an ambiguous question. You can use ASCII or ANSI colour codes in some shells I think... I'm pretty sure it does not work on the standard windows shell any more but it works in bash I think... So already it's becoming platform dependent. Anything else is all platform dependent. If you want to have colour on a text UI then look into ncurses: http://ndk-xx.sourceforge.net/ If you want a GUI then there are many options like GTK.

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Hi:

I don't know if anyone mentioned this, but I'd be curious if someone could comment on using Codeblocks compared to Bloodshed DevC++ as a noobie IDE. I'm tempted to get a Microsoft Visual C++ but I'm concerned about proprietary lockin in that all I'd ever be able to do is program Windows.

Thanks for any replies.

Jojo

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can any1 pls help my...why i'm getting this error on compiling

multiple definition of `function(double, double, double, double, double)'

the function is only declared once and there is the code for it, only 1 instance of it is in the whole file...

I'm using CodeBlocks latest nightly build

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can any1 pls help my...why i'm getting this error on compiling

the function is only declared once and there is the code for it, only 1 instance of it is in the whole file...

I'm using CodeBlocks latest nightly build

post ur source

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main file


#include "student.cpp"

int main() {

Student *alin = new Student("Alin", "Bata", "1870513350037", 2008, 6, 3, 5, 8, 4, 9);

alin->studentPrint();

ofstream store ("studenti.txt");
if (store.is_open()) {
store << alin->getNume() << alin->getPrenume() << alin->getMediaGenerala() <<
alin->getCrediteObtinute() << endl;
}
else cout << "Unable to open file" << endl;
store.close();

return 0;
}
[/codebox]

student.cpp file

[codebox]
#include <iostream>
#include <fstream>

#include "student.h"

using namespace std;

//constructors
Student::Student() {
this->nume = "";
this->prenume = "";
this->cnp = "";
this->promotia = 0;
this->grupa = 0;
this->notaAnalizaMatematica = 0;
this->notaProgramareC = 0;
this->notaAlgoritmica = 0;
this->notaBazeleInformaticii = 0;
this->notaEngleza = 0;
this->mediaGenerala = 0;
this->crediteObtinute = 0;
};

int calculcredite(double notaAnalizaMatematica, double notaProgramareC, double notaAlgoritmica,
double notaBazeleInformaticii, double notaEngleza);

Student::Student(string nume, string prenume, string cnp, int promotia, int grupa,
double notaAnalizaMatematica, double notaProgramareC, double notaAlgoritmica,
double notaBazeleInformaticii, double notaEngleza) {
this->nume = nume;
this->prenume = prenume;
this->cnp = cnp;
this->promotia = promotia;
this->grupa = grupa;
this->notaAnalizaMatematica = notaAnalizaMatematica;
this->notaProgramareC = notaProgramareC;
this->notaAlgoritmica = notaAlgoritmica;
this->notaBazeleInformaticii = notaBazeleInformaticii;
this->notaEngleza = notaEngleza;
this->mediaGenerala = ((notaAnalizaMatematica + notaProgramareC
+ notaAlgoritmica + notaBazeleInformaticii + notaEngleza) / 5);
this->crediteObtinute = calculcredite(notaAnalizaMatematica,
notaProgramareC, notaAlgoritmica, notaBazeleInformaticii, notaEngleza);
};

int calculcredite(double notaAnalizaMatematica, double notaProgramareC,
double notaAlgoritmica, double notaBazeleInformaticii, double notaEngleza) {
int temp = 0;
if(notaAnalizaMatematica >= 5) {
temp = temp + 6;
}
if(notaProgramareC >= 5) {
temp = temp + 6;
}
if(notaAlgoritmica >= 5) {
temp = temp + 6;
}
if(notaBazeleInformaticii >= 5) {
temp = temp + 6;
}
if(notaEngleza >= 5) {
temp = temp + 6;
}
return temp;
};

//deconstructors

//get functions
double Student::getMediaGenerala(void) {
return this->mediaGenerala;
};
int Student::getCrediteObtinute(void) {
return this->crediteObtinute;
};
string Student::getNume(void) {
return this->nume;
};
string Student::getPrenume(void) {
return this->prenume;
};

//print class
void Student::studentPrint(void) {
cout << this->nume << this->prenume << this->cnp << this->promotia << this->grupa <<
this->notaAnalizaMatematica << this->notaProgramareC << this->notaProgramareC <<
this->notaAlgoritmica << this->notaBazeleInformaticii << this->notaEngleza <<
this->mediaGenerala << this->crediteObtinute << endl;
};

student.h file //here is the class declared

#include <string>

using namespace std;

class Student {
public:
Student();
Student(string nume, string prenume, string cnp, int promotia, int grupa, double notaAnalizaMatematica,
double notaProgramareC, double notaAlgoritmica, double notaBazeleInformaticii, double notaEngleza);
~Student();
//get functions
string getNume(void);
string getPrenume(void);
double getMediaGenerala(void);
int getCrediteObtinute(void);
//print function
void studentPrint(void);
private:
string nume;
string prenume;
string cnp;
int promotia;
int grupa;
double notaAnalizaMatematica;
double notaProgramareC;
double notaAlgoritmica;
double notaBazeleInformaticii;
double notaEngleza;
double mediaGenerala;
int crediteObtinute;
};
[/codebox]

ty

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why did you double the same variable twice? :s

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why did you double the same variable twice? :s

mhh of what variable are you refering?

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problem solved, I included 1 file twice by mistake :(

ty Internet for help :)

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At first, I didn't really though many people would reply, Thanks. First, I think I am going to get started with C then move on to C++ and maybe create my first program(thinking too far ahead). Oh yeah, I am also 13 and I figure this is the best time to learn since I am yuong and I will get materials better. Again, Thanks for everything.

Ok shouldn't you try learning Visual Basic first? I tryed learning other languages first like WPF and stuff like that, it never worked out for me because Visual Basic is the beginning for programming. I never understood how programming worked, until I learned a little Visual Basic, which would help you learn the next programming language. Well I know this post is old, but it also is still valid for asking this question.

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I've found that you can't go wrong with a copy of C++ for Dummies and a Dev-C++ compiler.

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Have a look on this link..:

www.cplusplus.com/doc/tutorial/

Its really a best tutorial and with example of codes so go ahead man..Good luck..

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Have a look on this link..:

www.cplusplus.com/doc/tutorial/

Its really a best tutorial and with example of codes so go ahead man..Good luck..

It's a great group of tutorials :)

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I know I'm a little (very) late in this thread, but...

C++ is old! move to Java! it's much much better!

And better yet, focus on internet technologies, PHP or JSP or JSF and AJAX/CSS/XHTML

It's more fun than the old boring languages!

w3schools.com one of the best sources for most of them!

Edited by nonick

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C++ is old! move to Java! it's much much better!
Java is so 1995. It's about time we moved on to C#. Wait, C# is so 2001... :p

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