C/C++ Beginner's Guide and Post Basic Questions here

harshilsharma63

harshilsharma63

DIY FTW!
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Jul 2, 2012
Messages
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saswat23 said:
Explain me the output of this:

Code: 
void main()
{
float a=1.22; 
if (a==1.22) 
printf("C");
else 
printf("cD");
getch();
}
Click to expand...

Thats a classic! It's just one of many codes to represent the complex world of floating point numbers. So, this is what happens:

> 1.22 base 10 is (0.0011100001010001111010111000010100011110101110000101...) base 2.

> The bold part is the binary pattern that repeats till infinity.

> As we do not have infinite memory, so to store it in a memory, it is truncated and rounded off to (1.22000003) base 10.

> Since 1.22000003 is NOT equal to 1.22 (which is stored as 1.22000000 in a float variable), so the program executes the false parte instead of the true part of if-else code (debug the program to see the actual values).

> Have a look at this page: 2.5 — Floating point numbers « Learn C++

> Float numbers are beyond any webpage's scope!
 
velociraptor

velociraptor

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hey i wrote a prog in c++ using notepad and i cant get how to compile and execute it please tell in detail .i m using windows 8 and i have got the MinGW compiler installed
 
nightcrawler

nightcrawler

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Check out the MinGW wiki for First Time Users and the HOWTO guide on their site. It should solve all your problems and queries easily. Unless you are having problems in compiling itself.
 
Vyom

Vyom

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velociraptor said:
hey i wrote a prog in c++ using notepad and i cant get how to compile and execute it please tell in detail .i m using windows 8 and i have got the MinGW compiler installed
Click to expand...

You can either install Code::blocks, which after integration with MinGW, will give you a full fledge IDE. Or compile and run program from command line.

  1. Press Windows + R.
  2. Open Command Prompt.
  3. With CD command navigate to the "bin" folder where MinGW is installed.
  4. Compile the program:
    g++ cppfile.cpp -o output.exe
  5. And then run the output file by just entering the name of output file and pressing enter.
    output.exe


You could have also used c++ command as an alternative to g++.

PS: Of course you have to keep program in bin folder, or give full path of the cpp filename.
 
gameranand

gameranand

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velociraptor said:
hey i wrote a prog in c++ using notepad and i cant get how to compile and execute it please tell in detail .i m using windows 8 and i have got the MinGW compiler installed
Click to expand...

If you don't want any trouble and don't want to go the conventional way then you can use Code::Blocks. :)
 
somebodysme

somebodysme

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Dec 9, 2011
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139
For improving problem solving
*projecteuler.net
*www.codechef.com

Register and get started
 
nightcrawler

nightcrawler

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Swapnil26sps said:
In projecteuler.net, do they give solutions too?
Click to expand...
No not directly. They give you a problem and ask you for the output. If it is correct you have solved the puzzle. I believe once that is done you could access the forum to get the answer or something. Although not sure. Not been on projecteuler for last 2 years or so.
 
harshilsharma63

harshilsharma63

DIY FTW!
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Jul 2, 2012
Messages
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Swapnil26sps said:
In projecteuler.net, do they give solutions too?
Click to expand...
They have a forum for the purpose. However, I recommend to build the code yourself, get the correct answer, the optimize the code to the lowest complexity possible and then compare it with a code in the forum or elseware :)
 
kunalht

kunalht

In the zone
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Sep 7, 2012
Messages
392
Hii
I have just completed 12th sci.
Now I have vacation.
I want to learn programming in this vacation.
Which shold I learn HTML or C or C++ or JAVA ????
I want to learn this at home(without any classes)
can i learn it without classes??
& also plz suggest me some website or books or ebooks for learning that....
 
Nerevarine

Nerevarine

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Feb 6, 2011
Messages
8,566
python, learn it as a hobby..
Im learning it myself..
although.. u need basic OOP concepts to do any good
 
rohitshubham

rohitshubham

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Jul 20, 2008
Messages
550
Help Me with this code
Code: 
[COLOR=#339933]#include<stdio.h>[/COLOR]
 [COLOR=#993333]void[/COLOR] main[COLOR=#009900]([/COLOR][COLOR=#993333]void[/COLOR][COLOR=#009900])[/COLOR][COLOR=#009900]{[/COLOR]   
 [COLOR=#993333]long[/COLOR] x[COLOR=#339933],[/COLOR]y [COLOR=#339933];
[/COLOR] [URL="*www.opengroup.org/onlinepubs/009695399/functions/scanf.html"][COLOR=#000066]scanf[/COLOR][/URL][COLOR=#009900]([/COLOR][COLOR=#FF0000]"%l %l"[/COLOR][COLOR=#339933],[/COLOR] [COLOR=#339933]&[/COLOR]x[COLOR=#339933],[/COLOR] [COLOR=#339933]&[/COLOR]y[COLOR=#009900])[/COLOR][COLOR=#339933];
[/COLOR]   [COLOR=#B1B100]if[/COLOR][COLOR=#009900]([/COLOR]x[COLOR=#339933]>[/COLOR]y[COLOR=#009900])
[/COLOR]    [COLOR=#009900]{[/COLOR]    [URL="*www.opengroup.org/onlinepubs/009695399/functions/printf.html"][COLOR=#000066]printf[/COLOR][/URL][COLOR=#009900]([/COLOR][COLOR=#FF0000]"%l"[/COLOR][COLOR=#339933],[/COLOR]y[COLOR=#009900])[/COLOR][COLOR=#339933];[/COLOR]     [COLOR=#009900]}[/COLOR]  
  [COLOR=#B1B100]else[/COLOR]     [COLOR=#009900]{[/COLOR]     
[COLOR=#B1B100]       if[/COLOR][COLOR=#009900]([/COLOR]x [COLOR=#339933]%[/COLOR] [COLOR=#0000DD]5[/COLOR] [COLOR=#339933]==[/COLOR][COLOR=#0000DD]0[/COLOR][COLOR=#009900])[/COLOR]  
      [COLOR=#009900]{[/COLOR]         y[COLOR=#339933]=[/COLOR] y[COLOR=#339933]-[/COLOR]x [COLOR=#339933];[/COLOR]    
               y[COLOR=#339933]=[/COLOR]y[COLOR=#339933]-[/COLOR][COLOR=#800080]0.5[/COLOR][COLOR=#339933];
[/COLOR]               [URL="*www.opengroup.org/onlinepubs/009695399/functions/printf.html"][COLOR=#000066]printf[/COLOR][/URL][COLOR=#009900]([/COLOR][COLOR=#FF0000]"%l"[/COLOR][COLOR=#339933],[/COLOR] y[COLOR=#009900])[/COLOR][COLOR=#339933];
[/COLOR]     [COLOR=#009900]}[/COLOR]     
      [COLOR=#B1B100]else[/COLOR] 
       [COLOR=#009900]{[/COLOR]            [URL="*www.opengroup.org/onlinepubs/009695399/functions/printf.html"][COLOR=#000066]printf[/COLOR][/URL][COLOR=#009900]([/COLOR][COLOR=#FF0000]"%l"[/COLOR][COLOR=#339933],[/COLOR] y[COLOR=#009900])[/COLOR][COLOR=#339933];[/COLOR]                [COLOR=#009900]}[/COLOR]     
[COLOR=#009900]}
[/COLOR]     [COLOR=#009900]}[/COLOR]
It's Giving me runtime error

Help Me with this code
Code: 
[COLOR=#339933]#include<stdio.h>[/COLOR]
 [COLOR=#993333]void[/COLOR] main[COLOR=#009900]([/COLOR][COLOR=#993333]void[/COLOR][COLOR=#009900])[/COLOR][COLOR=#009900]{[/COLOR]   
 [COLOR=#993333]long[/COLOR] x[COLOR=#339933],[/COLOR]y [COLOR=#339933];
[/COLOR] [URL="*www.opengroup.org/onlinepubs/009695399/functions/scanf.html"][COLOR=#000066]scanf[/COLOR][/URL][COLOR=#009900]([/COLOR][COLOR=#FF0000]"%l %l"[/COLOR][COLOR=#339933],[/COLOR] [COLOR=#339933]&[/COLOR]x[COLOR=#339933],[/COLOR] [COLOR=#339933]&[/COLOR]y[COLOR=#009900])[/COLOR][COLOR=#339933];
[/COLOR]   [COLOR=#B1B100]if[/COLOR][COLOR=#009900]([/COLOR]x[COLOR=#339933]>[/COLOR]y[COLOR=#009900])
[/COLOR]    [COLOR=#009900]{[/COLOR]    [URL="*www.opengroup.org/onlinepubs/009695399/functions/printf.html"][COLOR=#000066]printf[/COLOR][/URL][COLOR=#009900]([/COLOR][COLOR=#FF0000]"%l"[/COLOR][COLOR=#339933],[/COLOR]y[COLOR=#009900])[/COLOR][COLOR=#339933];[/COLOR]     [COLOR=#009900]}[/COLOR]  
  [COLOR=#B1B100]else[/COLOR]     [COLOR=#009900]{[/COLOR]     
[COLOR=#B1B100]       if[/COLOR][COLOR=#009900]([/COLOR]x [COLOR=#339933]%[/COLOR] [COLOR=#0000DD]5[/COLOR] [COLOR=#339933]==[/COLOR][COLOR=#0000DD]0[/COLOR][COLOR=#009900])[/COLOR]  
      [COLOR=#009900]{[/COLOR]         y[COLOR=#339933]=[/COLOR] y[COLOR=#339933]-[/COLOR]x [COLOR=#339933];[/COLOR]    
               y[COLOR=#339933]=[/COLOR]y[COLOR=#339933]-[/COLOR][COLOR=#800080]0.5[/COLOR][COLOR=#339933];
[/COLOR]               [URL="*www.opengroup.org/onlinepubs/009695399/functions/printf.html"][COLOR=#000066]printf[/COLOR][/URL][COLOR=#009900]([/COLOR][COLOR=#FF0000]"%l"[/COLOR][COLOR=#339933],[/COLOR] y[COLOR=#009900])[/COLOR][COLOR=#339933];
[/COLOR]     [COLOR=#009900]}[/COLOR]     
      [COLOR=#B1B100]else[/COLOR] 
       [COLOR=#009900]{[/COLOR]            [URL="*www.opengroup.org/onlinepubs/009695399/functions/printf.html"][COLOR=#000066]printf[/COLOR][/URL][COLOR=#009900]([/COLOR][COLOR=#FF0000]"%l"[/COLOR][COLOR=#339933],[/COLOR] y[COLOR=#009900])[/COLOR][COLOR=#339933];[/COLOR]                [COLOR=#009900]}[/COLOR]     
[COLOR=#009900]}
[/COLOR]     [COLOR=#009900]}[/COLOR]
It's Giving me runtime error
 
harshilsharma63

harshilsharma63

DIY FTW!
Joined
Jul 2, 2012
Messages
6,430
^ At least mention the error and the input for which you are getting this error.

oops, krishnandu.sarkar's post cane beteen.
 
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