Hi,
I have got to declare using namespace std first.
Then I have got to use std:: -> (display a list of function) for std.
I just want to do File *f =
I need to type std::->(generate function)->fopen() and delete std again.
So troublesome.
Furthermore, for C++ i need to put File * f, this asterisk,unlike java I can just ignore the *.
FILE *f = fopen("test.txt","r"); // why the need for an * again i recall in java only need to File f = new File("test.txt");
while(fgets(line,80,f) != NULL){ // in java NULL or null doesn't matter
printf("%s",line);//in java I can use System.out.println(""); is there a shorter way to print out the line
}
Ok,to take on any programming assignment,we need to know at the how to do this.Anything missing please advice.
- Write a Hello World
- Create a Loop
- Display item(s) in an array
- Read a .txt file
Dear twinbaby,
if you find certain things at this novice level "troublesome" and "inconvenient", I highly recommend that you drop your pursue on Computer Science. Clearly Computer Science is not going to be simple and hence words like "troublesome" and "inconvenient" contradicts with the fundamental spirit of Computer Science. Computer Science is to make things possible, and making things possible doesn't necessarily has to be "simple" and "convenient".
I hope you get this hardcoded into your mindset, change your attitude looking at technology and then decide if you want to continue pursue on this matter ? Is that alright ?
First of all, I would like you to discard on Java and learn C++ the way it was meant to be. The general concepts of computing can be retained, but empty your cup on what Java has taught you and learnt C++ from its fundamental. Just like how English is different from Mandarin, we don't complain that English only has 26 alphabets and words are made out of them, while Mandarin comes in strokes but with over tens of thousands of different characters. It's how these 2 programming languages differs. If you think an extra '*' confuse you, you have not seen the real thing at all. Start into C++ STL and you will see even more quirkiness in language itself.
First of all, Java only has Reference construct, it does not offers Pointer construct. Pointers are more powerful than just References. C++ has both Pointers and References. However even so, References in C++ are declared using '&', Eg: int x; int& y = x;
If you want to skip what I am going to say from this point onwards, please go pick up a C++ Beginners book from the nearest National Library, such as
Amazon.com: Ivor Horton's Beginning ANSI C++: The Complete Language (Expert's Voice) (9781590592274): Ivor Horton: Books.
You will find no lacking of such books in the library since C++ has be around for a very long time. If anyone recommend you should start with C++11, forget that advice. What you need is fundamentals on C++.
Using namespace, C++ will not know which package does a symbol belongs to, if it is not declared in the same file or included. For included header files(also known as declaration files), a lot of them uses namespaces to separate their symbol from other libraries. The standard libraries in C++ own the "std" namespace. As such, standard tools like cin, cout and a lot more other such variables/objects, classes or functions are to be referred using std::* namespace.
For "File *f", f is a pointer variable. It store memory addresses and points to a type "File". In this case, type "File" is a structure.
Below is a simple example of how you can play with References and Pointers.
Code:
#include <iostream>
using namespace std;
int main(int argv, char** argc) {
int i;
FILE *f = NULL;
f = fopen("my.txt", "r");
FILE& rf = *f;
char s[1024];
fgets(s, 100, &rf);
printf("%p %s", f, s);
fclose(f);
return 0;
}
Those methods of reading file using fgets, open a file using fopen are not exactly part of C++. They are established in C language. C++ has its own way of manipulating I/O. Please read up
Input/output with files - C++ Tutorials
Who set you the standard of what you should know in order to complete C++ assignments ? You might want to refer to the tutor or institute that is setting you such standards based on their syllabus. My standard of what a C++ programmer should know is a far longer list that what you have provided.
