little help about my program in c++

Fulkan · 12-10-2004, 03:58 PM

Hi@all

I just started to learn C++. I am in trouble with reading integers. I am suppose to write a little program but I have a problem.

In my program, I should read 10 integer values from keyboard and hold them in an array. My program has to halt input either eof or array is full. After that echo each array.

example;

input 1 2 3 4 5 6 7
output 1 2 3 4 5 6 7

My problem is when I use cin for reading values, it skips white space. My loop never ends until array is full. I mean when I want to read and hold 8 numbers, it doesn't work. Can someone show me how to I can write the program?

My code;

Code:

#include <iostream>
using namespace std;
int main()
{
const int size=10;
int array[size];
int input; 
int actual=0; // counter how many numbers are read until eof
input=cin.get();
while (input!=cin.eof()&&actual<size)
{
array[actual]=input;
actual++;
input=cin.get();
}
for (int i=0; i<actual; i++)
cout <<a[i];
return 0;
}

thanks

Hko · 12-10-2004, 04:04 PM

Quote:

Can someone show me how to I can write the program?

Without the code you have problems with, we'll have to guess where the problem is...

Asking to do your homework is not fair, doesn;t really help you learn, and it's against this forum's rules. If you get stuck, and post the code you have so far, we can help of course.

Fulkan · 12-10-2004, 04:13 PM

Hi@ Hko

I am sorry. I forgot to add my code. I am adding my code in my first message now. Actually, my program that I asked for help is the part of my homework but I am not asking whole program. I am asking where I am stuck on it. I think it is fair. I am trying to learn.

When I wrote this code for char, it works. I wonder why it doesn't work for integers.

thanks

gaffel · 12-10-2004, 06:46 PM

it doesn't work for integers because it work for chars.

use some debug options and look at what value cin.get() actually returns into variable input.
Then think about what a char actually is.

Hivemind · 12-11-2004, 06:23 AM

Here's one solution.
It reads until ten integers has been read or until a reading
error occurs. One might consider a solution where one tries to
recover from a reading error and continue to read but that is left
as an exercise for the reader.

Code:

#include <iostream>
#include <limits>

using std::cerr;
using std::cout;
using std::cin;
using std::endl;
using std::flush;
using std::numeric_limits;
using std::streamsize;

int main()
{
   const unsigned short array_size = 10;
   int integer_array[array_size];
   unsigned short current_index = 0;
   int n = 0;

   /* Reads until ten integers has been read or a *
    * reading error occurs. Anything that's left  *
    * in the stream after that is discarded.      */
   while(cin >> n && current_index < array_size)
   {
      integer_array[current_index++] = n;
   }

   if(!cin.good())
   {
      cerr << "cin is in a bad state." << endl;
      cerr << "That means input not automatically "
           << "convertible to int was encountered "
           << "in the input stream." << endl
           << "Clearing error bit so we can discard any "
           << "input left in the stream." << endl;

      /* All operations on the stream, except clear(), are no-ops *
       * until the fail/bad-bit has been cleared.                 */
      cin.clear();
   }

   /* Discarding remaining input in the stream, if any. */
   cin.ignore(numeric_limits<streamsize>::max());

   cout << "Read " << current_index << " integers." << endl;

   for(int i = 0; i < current_index; ++i)
   {
      cout << integer_array[i] << " ";
   }

   cout << flush;

   return 0;
}

obashir · 12-12-2004, 08:25 AM

With reference to the original program, cin.get() returns the ascii value of a char therefore it works for characters.

More info at

http://www.cplusplus.com/ref/iostream/istream/get.html

Regards,

OMAR.