C++ problem need your input

Hi, I'm a total beginner in C++. I am using Bloodshed Dev C-++ 4.01 Compiler. Now Im trying to get Hello World program to run, it compiles successfully but it won't Run. The command prompt blinks for one second and it disappears. Basically, it wont execute. I've enlist the help of Mathgirl but shes not too familiar with the compiler Im using, I've looked through this thread
I followed it but it wont work.


It's from the book teach Yourself C++ in 24 hours, although It'll take more than that.

This is the program I did:

#include <iostream>

int main()
{
std::cout << "Hello World!\n";
return 0;
}

It compiles successfully but like I said before it won't execute, I can't see the result Hello World. How do I get this simple program up and running? I appreciate any help.

Vin, try this link, regarding system(“PAUSE”); .

add the following line to your code :
add to the end, just before the return 0.

getch();


Another option is, first compile the code, run it, and press Alt+F5 to view the output.

Invader, I use MS VisualC++6.0 and suggested in a PM that M/S Vin use getch();
but it didn't work. I don't use Bloodshed but getch(); worked for me when I tried out his program.

Strange. even the Alt+F5 didnt work ?

1)I don't think there is an option to see the o/p using alt+F5 in Dev C++. the simplest thing is to include a getch() statement at the end of ur prog.

2) Otherwise , u can run ur program thru the command prompt. just *cd* to the directory where ur prog is and then just enter the name of ur prog.

#include <iostream>

int main()
{
cout << "Hello, World!\n";
cin.ignore();

return 0;

}

Quote:

---

Originally posted here by invader
add the following line to your code :
add to the end, just before the return 0.

getch();


Another option is, first compile the code, run it, and press Alt+F5 to view the output.

---

When I click compile, it compiles successfully like I said before, right after; I click Run all I see is a blink with no output of the program.

Quote:

---

Originally posted here by shantz
1)I don't think there is an option to see the o/p using alt+F5 in Dev C++. the simplest thing is to include a getch() statement at the end of ur prog.

2) Otherwise , u can run ur program thru the command prompt. just *cd* to the directory where ur prog is and then just enter the name of ur prog.

---

I've tried the getch(); command over and over but it really wont work.
Here it is:

#include <iostream>

int main()
{
std::cout << "Hello World!\n";
get ch();
return 0;
}

Error Message is : Each undeclared identifier is reported only once for each function it appears in.
Parse error before (

Hey Vin, U r using the getch() instruction wrongly. there is no space between get and ch as u wrote "get ch(); ". Try "getch();" (without the quotes obviously).
Moreover, I don't quite remember clearly, but I think u need to include "conio.h" too.
And yes, the second method I told must surely work.
Hope that helps

Quote:

---

Originally posted here by er0k
#include <iostream>

int main()
{
cout << "Hello, World!\n";
cin.ignore();

return 0;

}

---

Erok, this one worked! Thanks! I appreciate it, and if anyone have some more to add please feel free to do so.

WTF, ive never used Bloodshed before, use turbo, simple and best :p
but shantz is right, getch(); is a function and one word.
And shantz, getch() is included in iostream, except if you're using a 2-3 year old compiler.

What command was that er0k ?
I don't think commands change when compilers change.
I mean i neva heard o that one before.

One more thing, does Bloodshed dominate users in America ?
duh, i mean the compiler.

Quote:

---

Originally posted here by M/S Vin


Erok, this one worked! Thanks! I appreciate it, and if you have some more to add please feel free to do so.

---

np... anytime, im also new to C++ just have been through that b4 :)

invader >> that is the function you use with the standard library's on a simple output statement for it to stay "on screen" you can use the system('pause') as well its just not always portable. the cin.ignore() function is built in..

edit >> sometimes its good practice to try something similar to this: ( if you are doing std work)

#include <iostream>

using namespace std;

built inside iostream ?

its a built in function yes, and iostream is a pre-processor directive that contains it yes to be frank. sorry id get you some more info from muuuucccch better programmers, ie a C++ book, but i need sleep.

C++ uses streams for input and output (this replaces C's printf() scanf() although still availible).

Streams are in fact objects....
You have four console streams automatically availible: cin, cout, cerr, clog

cin reads from the console (standard input), cout writes to the console (standard output)...

cin is an istream (actually it's derived from istream...)
the class istream defines, amonst others, the operator ">>" (ie: operator>>() )
which you use to read from a stream, in cin's case the stream is the standard input so it "reads from the keyboard".

cout is an ostream
the class ostream defines the operator "<<" (ie: operator<<() )
which you use to write to a stream, in cout's case the standard output, so it "writes to the screen".

as for cin.ignore():
ignore() is a method of the class istream; by default (without params) it reads 1 character (or up to EOF) from the standard input ("keyboard") and discards it. Ie: it makes the application wait for the user to enter a character before continuing...

Hope this clears things up...

Ammo

The function getch() and the Alt+F5 combo work only with Turbo/Borland C++. So you have to use system("pause"); instead.
Cheers,
cgkanchi

Quote:

---

as for cin.ignore():
ignore() is a method of the class istream; by default (without params) it reads 1 character (or up to EOF) from the standard input ("keyboard") and discards it. Ie: it makes the application wait for the user to enter a character before continuing...

---

urmm...doesnt getch() do the same ? Get a character from the user before continuing..
Thanks anyway, ammo

#include<stdlib.h>
#include<conio.h>
#include<iostream.h>
void main(){
cout<<"Hello world";
cout<<"\npress any key to quit....";
while(getch()=='\0'){
}
_exit(0);
}

Quote:

---

Originally posted here by invader
WTF, ive never used Bloodshed before, use turbo, simple and best :p

---

Im in enough confusion as it is.

Quote:

---

Originally posted here by cgkanchi
The function getch() and the Alt+F5 combo work only with Turbo/Borland C++. So you have to use system(&quot;pause&quot;); instead.
Cheers,
cgkanchi

---

System pause didn't work either, and I get the message Implicit declaration of function int getch (...) But thanks.

Quote:

---

Originally posted here by black_death
#include&lt;stdlib.h&gt;
#include&lt;conio.h&gt;
#include&lt;iostream.h&gt;
void main(){
cout&lt;&lt;&quot;Hello world&quot;;
cout&lt;&lt;&quot;\npress any key to quit....&quot;;
while(getch()=='\0'){
}
_exit(0);
}

---

I've tried the one you PM, it compiled successfully but It didn't run.

Anymore help/info that you want to add, feel free to do so.

Thank you for all the help .

To use the system("pause") command you have to #include <cstdlib> at the beginning of the program. If that doesn't work, use #<stdlib.h>. And if that still doesn't work, get a real compiler at http://borland.com.
Cheers,
cgkanchi

Quote:

---

Originally posted here by invader

urmm...doesnt getch() do the same ? Get a character from the user before continuing..
Thanks anyway, ammo

---

First, getch() isn't a standard call, and won't be availible on all systems; however, the standard C way of reading a single char from the standard input is getchar()
(int getchar())
which IS standard and can be found in stdio.h
(#include <stdio.h> ).

The exact equivalent with C++ streams would be:
cin.get()

both ways read a single char from the standard input and returns it...
but since we're not interested in what that character is going to be (ie: we're not gonna use it), we might as well do a
cin.ingore()
as er0k mentionned previously.

So both ways work, it's just a question of consistency:
if you're using iostreams for IO (cin, cout...) in your C++ prog, you should stick with it and use cin.ignore(); or cin.get();
if you're using stdio's (scanf(), printf()) you should stick with it and use getchar();

Ammo

Quote:

---

Originally posted here by ammo


First, getch() isn't a standard call, and won't be availible on all systems; however, the standard C way of reading a single char from the standard input is getchar()
(int getchar())
which IS standard and can be found in stdio.h
(#include <stdio.h> ).

The exact equivalent with C++ streams would be:
cin.get()

both ways read a single char from the standard input and returns it...
but since we're not interested in what that character is going to be (ie: we're not gonna use it), we might as well do a
cin.ingore()
as er0k mentionned previously.

So both ways work, it's just a question of consistency:
if you're using iostreams for IO (cin, cout...) in your C++ prog, you should stick with it and use cin.ignore(); or cin.get();
if you're using stdio's (scanf(), printf()) you should stick with it and use getchar();

Ammo

---

So basically, If Im using iostream, I have to type cin.ignore(); at the end of any program to see my
output. Very cool Ammo.

Well it's not that you *have to* to see your program's output: it's that when you lunch a console program in windows, when the progam ends, windows automatically closes the console window that was launched... adding cin.ignore() only delays the end of the program until user input. It's not really a programming issue of its own..

If you were to start a command prompt first (run: cmd.exe (NT/2000) command.com (95/98)) the go to the directory you're program is in (cd c:\blah\blah) and then run it from there (myprog.exe), your prog would execute in that console window which would stay opened because it was opened manually (ie: not by the program itself)... (This was mentionned by shantz in his post)...


Ammo

Quote:

---

Originally posted here by M/S Vin
Hi, I'm a total beginner in C++. I am using Bloodshed Dev C-++ 4.01 Compiler. Now Im trying to get Hello World program to run, it compiles successfully but it won't Run. The command prompt blinks for one second and it disappears. Basically, it wont execute. I've enlist the help of Mathgirl but shes not too familiar with the compiler Im using, I've looked through this thread
I followed it but it wont work.


It's from the book teach Yourself C++ in 24 hours, although It'll take more than that.

This is the program I did:

#include <iostream>

int main()
{
std::cout << "Hello World!\n";
return 0;
}

It compiles successfully but like I said before it won't execute, I can't see the result Hello World. How do I get this simple program up and running? I appreciate any help.

---

[ANSWER]
Remove the space between include and <iostream>
correct is:
#include<iostream>
[/ANSWER]

#include <iostream.h>

int main()
{
cout << "Hello World ! \n" ;

return 0 ;

}

This worked for me just fine,I really dont see what the problem is ?maybe it's your compiler or your typeing in the wrong command.

Quote:

---

Originally posted here by djc314159

[ANSWER]
Remove the space between include and <iostream>
correct is:
#include<iostream>
[/ANSWER]

---

First I have to admit to an error, removing the space between <iostream> and include
is not the answer. I've looked further into the problem and here's what I found.

I'm running Windows xp and have the latest updates to both Windows and bloodshed c++.
When I run the referred to program I get 70 compiler errors:
typical error:
In file iostream
line 44 is bits/c++config.h, there is no such file or directory.

Indeed when I looked at file iostream it does refer to bits/c++config.h which is nonexistant,
however ming32/c++config.h does exist, hence all (or at least most) of the errors.

I sent an bug report to bloodshed via a forum and am awaiting an answer. I'll report here what
the say.

Sorry for the error.

Quote:

---

Originally posted here by djc314159


First I have to admit to an error, removing the space between <iostream> and include
is not the answer. I've looked further into the problem and here's what I found.

I'm running Windows xp and have the latest updates to both Windows and bloodshed c++.
When I run the referred to program I get 70 compiler errors:
typical error:
In file iostream
line 44 is bits/c++config.h, there is no such file or directory.

Indeed when I looked at file iostream it does refer to bits/c++config.h which is nonexistant,
however ming32/c++config.h does exist, hence all (or at least most) of the errors.

I sent an bug report to bloodshed via a forum and am awaiting an answer. I'll report here what
the say.

Sorry for the error.

---

I recieved a reply to my bug report.
Their suggestions follow:

Solution Number 1:

Copy the files of C:\Dev-Cpp\include\c++\mingw32\bits

to C:\Dev-Cpp\include\c++\bits

Solution Number 2:

Add C:\Dev-Cpp\include\c++\mingw32 to compiler/directories/C++ includes

For more information:

Goto the bloodshed forum: (use the about button to locate it)
Search for 4.9.7.0
Expand search: 4.9.7.0 BlackJak
or 4.9.7.0 DerekBaker

More: They reccommend trying solution 2 first since it's less intrusive.
I'm going to proceed to try to fix my problem using these suggestions.
In other words "physician heal thyself".
I'll report on my progress or lack thereof.
Remember, we're dealing with a Beta version and these kinds of problems
should be expected, so be patient.
Also, as they say "You get what you pay for".

Quote:

---

Originally posted here by djc314159


I recieved a reply to my bug report.
Their suggestions follow:

Solution Number 1:

Copy the files of C:\Dev-Cpp\include\c++\mingw32\bits

to C:\Dev-Cpp\include\c++\bits

Solution Number 2:

Add C:\Dev-Cpp\include\c++\mingw32 to compiler/directories/C++ includes

For more information:

Goto the bloodshed forum: (use the about button to locate it)
Search for 4.9.7.0
Expand search: 4.9.7.0 BlackJak
or 4.9.7.0 DerekBaker

More: They reccommend trying solution 2 first since it's less intrusive.
I'm going to proceed to try to fix my problem using these suggestions.
In other words "physician heal thyself".
I'll report on my progress or lack thereof.
Remember, we're dealing with a Beta version and these kinds of problems
should be expected, so be patient.
Also, as they say "You get what you pay for".

---

Finally: I got my system to compile and run the subject program exactly as first reported.
I used solution 2 above.
I've detailed how I solved my problem in my latest journal entry.
I'm not saying this is the only solution, or the best solution, but it is the one
reccommended by BlackJak and it works for me.
It's worth noting that original problem my be something different since it was
originally reported that the system compiled ok but would not run. To run the
compiled program you should be in a DOS window not the I.D.E.

It's really not the same problem as the original poster's... OP's problem was simply that it executed in a console window which closed immediatly after program ended.

Ammo

Everyone keeps posting complicated functions that don't seem to work so try this simple one:

#include <iostream.h>

int main()

{
int x;

cout << "Hello World!" << endl;
cin >> x;

return 0;
}

I started learning C++ not that long ago, 5/6 months to be exact, and I really like Bloodshed, not only cause its free but because its a got nice GUI.

Shouldnt there be an option to stop the output window from being killed so fast?

In a class i took using MS Visual C++ 6.0, it never happened, but on my personal MS Visual C++ 6.0, exactly the same, i barely see the output window open, unless i use an input to stop it...

I was going to let this thread fade into obscurity. I appreciate you all for taking the time to help me. I will try each and every suggestion. Problem has been solved. No more replies needed :)