Question involving using math operations...

Alright, I had posted a while ago about a project asigned to us by a teacher involving payrolls and everything. Well, I ditched the whole way we were doing it and started over with something that I hope will work better and it won't open all the files at once. :D Well, here's my question, I would like to multiply two values in 2 seperate files and have it displayed in another statement. I tried something simple:

Code:

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ammount=buffer*5+buffer2;
printf("The total ammount of money owed to Matt is %i.\n",ammount);

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buffer and buffer2 are the variables where the numbers in the files are stored. I was wondering why this won't work and if there might be a better way to do it (personally, I don't like to use the printf statement, as it looks sloppy to me). I get an error that says:

Quote:

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error C2296: '*' : bad left operand

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I'm just wondering, thanx...

Code:

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amount = buffer * 5 + buffer2;

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works for me.
How have you declared amount and buffer and buffer2.

yup.. I have them defined as an int and charters. uuuummm... I'll post the code I have so far for that section. Maybe it's something in the code that's doing it...

Code:

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int mattbview()
{
  char buffer[256];
  char buffer2[256];
  int ammount;
  ifstream mattb ("files/mattb.txt");
  ifstream mattb2 ("files/mattb2.txt");
  if (! mattb.is_open() && mattb2.is_open())
  {
          cout << "Error opening file";
          EXIT
  }

  while (! mattb.eof() )
  {
    mattb.getline (buffer,100);
        mattb2.getline (buffer2,100);
        cout << endl << "Name:  Matt Bilcliff";
        cout << endl << "Pay $5/hour";
        cout << endl << "Matt has worked ";
    cout << buffer;
        cout << " hours.";
        cout << endl << "The boss has given a bonus of ";
        cout << buffer2;
        cout << " dollars";
        ammount = buffer * 5 + buffer2;
        printf("The total ammount of money owed to Matt is %i.\n",ammount);
        mattb.close();
        mattb2.close();
  }
  return 0;
}

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Yes, it's not the cleanest mess of anything, but it's a start for now. I'll slim it down and try different things out later. lol.. Noticed that I like the cout to display the text? :D

buffer and buffer2 should either be integers or floating point numbers as you can't multiply character arrays.

alright. Thanx for telling me. Maybe I can get it working now.


[edit]
When I change char to int and have int buffer; instead of char buffer[256];, I get an error that says:

Quote:

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error C2664: 'class istream &istream::getline(char *,int,char)' : cannot convert parameter 1 from 'int' to 'char *'

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Any ideas? I believe that it has something to do with this part:

Code:

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mattb.getline (buffer,100);
mattb2.getline (buffer2,100);

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But I'm not positive

Try this:
Leave buffer and buffer2 as char arrays, and change this:
ammount = buffer * 5 + buffer2;

to this:
ammount = atoi(buffer) * 5 + atoi(buffer2);

Function atoi() is in <stdlib.h>.

Quote:

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Originally posted by swoopy
Try this:
Leave buffer and buffer2 as char arrays, and change this:
ammount = buffer * 5 + buffer2;

to this:
ammount = atoi(buffer) * 5 + atoi(buffer2);

Function atoi() is in <stdlib.h>.

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Thanks a lot. It worked perfectly. Now I gotta figure out how to stop the text from repeating. I recieve the following:

Quote:

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Name: Mat Bilcliff
Rate: $5/hour
Matt has worked 12 hours
The total ammount of money owed to Matt is 72.
The boss has given a bonus of 12 dollars.
Name: Mat Bilcliff
Rate: $5/hour
Matt has worked hours.
The total ammount of money owed to Matt is 0.
The boss has given a bonus of dollars

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uuummm... It seems the bonus is out of order too. uuuummmm... I think it maybe a loop screwed up somewhere.