I do have an option for exit. But here, its taking the input correctly and even going to the display segment.

But it doesn't display anything there.

It doesn't enter the while loop at all(refer code). I don't know why.

I've tried manipulating the file pointers in several ways, but none seem to work.

Thanks for helping though!

If you have other suggestions, do post!

I'm writing a program for data handling using files in c++.

I have provisions for inserting, deleting, modifying and displaying records.

This is menu driven, hence after you do one of these, it prompts you for another action.

ie

while(ch)

cin>>ch;

switch(ch)

{case 1:  //insert

case 2://modify

//and so on

}

The problem is, once I modify an element, it prompts for another action, as required. This time, it takes the input but doesn't give the output. It shows output correctly in the next prompt.

What could be the reason for this?

Am enclosing relevant parts of code :

'file' is an fstream object tied to the concerned file.

//modification

cout<<"\nEnter itemcode of item to be modified ";

                  cin>>icode;

                  file.seekg(0,ios::beg);

                  while(file)

                  {     file.read((char*)&i,sizeof(i));

                        if(icode==i.givedata()&&file)

                        {  pos=file.tellg();

                           cout<<"\npos="<<pos<<endl;

                           cout<<"\nEnter new values\n";

                          i.getdata();

                           file.seekg(pos-sizeof(i));

                          file.write((char*)&i, sizeof(i));

                       }

                  }

                  file.seekg(ios::end);

 //display

file.seekg(0,ios::beg);

      cout<<"\nContents of file\n";

       file.seekp(0,ios::beg);

      while(file.read((char*)&i,sizeof(i)))

           i.putdata();      

         file.clear();

                  break;

Please help soon.

Rates assured.

Thanks:-)                

Thanks. So in the end its nearly all hit and trial, is it?

Hi !

Could anyone help me with determinant proofs in which you need to use properties?

It'd be great if you could explain how to identify sums and which property to use, or rather what techniques you use to recognise patterns in the determinant.

Thanks!

Rates assured!

:-)

I did the verification of gas laws.

Try investigation of water samples

Or study the setting of cement

Or Extraction of iron from spinach leaves

Or experiment showing equilibrium

Check www.sirazenet.com/chemistry

For q12, use :

 mod(V_ab) =rt(v_a² + v_b² - 2v_av_b cos @.)...............ie relative motion formula..

So for maximum magnitude velocity, @ =90..

Thus he should swim straight!

Simple isnt it,once you know the formula?

For q13, make the triangle between one pulley, mass and the point straight above it.Differentiate length of string and you'll get the solution.

Try it.If you dont get it, visit :

http://www.goiit.com/posts/list/mechanics-please-fin-velocity-33091.htm

hmm...one of my friends had done a sudoku game using C++ as 11th project...

So I think solving should also be possible!!

Please reply someone!!!

Principal axis of what?

See, the two parts cant converge...they just bend light...so there isnt any question of the two 'separate lenses' forming different images?

Why don't you just put a pencil in front of a lens and try to converge sunlight on the ground?

Just try it!!!

But if all that is true, you mean to say the people who faked the photos were so dumb??

Moreover, in today's world, a fake like that wouldn't survive, there'd be a million people to pull it down...

What say?

C'mon..its there even in 10th NCERT text,about mirrors.

Extrapolate that a little if you dont believe the reasons given by all of us!!

@visa....see the figure given on page1....its just painted in the centre!!

What you are sayin will happen only if you BREAK the lens and SEPARATE the pieces!!

Check it out :

http://www.goiit.com/posts/list/general-effect-of-water-33370.htm

See the attached figure.

When the sun is at the horizon, the rays travel more distance through the Earths atmosphere.Hence they get scattered more, and red, having highest wavelength,travels faster.

When sun is overhead, it traverses less distance in the atmosphere and thus has less scattering.

This is also the reason why it looks bigger at sunrise and sunset.