Hey guys, i am relatively new at this programming thing and am stuck on an
assignment here. I'm trying to get the program below to respond to the
integer -1 to stop and calculate total. It does, but it makes me enter -1
under both gallons and miles, how can i avoid this? Thanks.
//Figures gas mileage in gallons
#include <iostream>
#include <conio.h>
using std::cout;
using std::cin;;
using std::fixed;
#include <iomanip>
using std::setprecision;
// function main begins program execution
int main()
{
int gal; //number of gallons used
int miles; //number of miles driven
int tg; //total of all gallons used
int tm; //total of all miles driven
double mpg; //miles per gallon
double total; //average of all drives
//initialization phase
tg = 0;
tm = 0;
while ( gal != -1 ) {
cout << "\nEnter the gallons used (Enter -1 to finish) :\n";
cin >> gal;
cout << "Enter the miles driven:\n";
cin >> miles;
tg = tg + gal;
tm = tm + miles;
//calculate miles per gallon
mpg = static_cast < double > ( miles ) / gal;
cout << "The per gallon for this trip were :\n" << setprecision ( 6 ) <<
fixed << mpg;
}
if ( gal != 0 )
total = static_cast < double > ( tm ) / tg;
cout << "\nThe overall average was:\n";
cout << total;
;return 0;
} 7 2648
Eric Whittaker wrote: Hey guys, i am relatively new at this programming thing and am stuck on an assignment here. I'm trying to get the program below to respond to the integer -1 to stop and calculate total. It does, but it makes me enter -1 under both gallons and miles, how can i avoid this? Thanks.
//Figures gas mileage in gallons
#include <iostream> #include <conio.h>
using std::cout; using std::cin;; using std::fixed;
#include <iomanip>
using std::setprecision;
// function main begins program execution int main() { int gal; //number of gallons used int miles; //number of miles driven int tg; //total of all gallons used int tm; //total of all miles driven
double mpg; //miles per gallon double total; //average of all drives
//initialization phase tg = 0; tm = 0;
total = 0.0;
// while ( gal != -1 ) {
for (;;) { // loop forever
cout << "\nEnter the gallons used (Enter -1 to finish) :\n"; cin >> gal;
if (gal < 0) // quit loop on negative gallons
break;
// ignore 0 gallons to prevent divide-by-zero error in 'mpg' calc
if (gal == 0)
continue;
cout << "Enter the miles driven:\n"; cin >> miles;
tg = tg + gal; tm = tm + miles;
//calculate miles per gallon mpg = static_cast < double > ( miles ) / gal;
cout << "The per gallon for this trip were :\n" << setprecision ( 6 ) << fixed << mpg; }
// if ( gal != 0 )
if (tg > 0) total = static_cast < double > ( tm ) / tg; cout << "\nThe overall average was:\n"; cout << total;
// ;return 0;
return 0; }
Regards,
Larry
--
Anti-spam address, change each 'X' to '.' to reply directly.
Hey thanks larry, the use of (for) is very helpful there. I'm just trying to
learn here, cause my assignment wants me to use a (while) structure to
accomplish this task, is this possible, when i try it keeps giving me a
"undeclared identifier - gal" error.
Thanks for all your help.
For future reference, a more informative subject line than "Help" would be a
good idea.
"Eric Whittaker" <ew****@adelphia.net> wrote in message
news:oe********************@adelphia.com Hey guys, i am relatively new at this programming thing and am stuck on an assignment here. I'm trying to get the program below to respond to the integer -1 to stop and calculate total. It does, but it makes me enter -1 under both gallons and miles, how can i avoid this? Thanks. //Figures gas mileage in gallons
#include <iostream> #include <conio.h>
using std::cout; using std::cin;; using std::fixed;
#include <iomanip>
using std::setprecision;
// function main begins program execution int main() { int gal; //number of gallons used int miles; //number of miles driven int tg; //total of all gallons used int tm; //total of all miles driven
double mpg; //miles per gallon double total; //average of all drives
//initialization phase tg = 0; tm = 0;
Note that the first time gal != -1 is encountered, gal is uninitialised. You
should set it equal to some initial value that is unequal to -1.
while ( gal != -1 ) { cout << "\nEnter the gallons used (Enter -1 to finish) :\n"; cin >> gal;
The problem here is that the gal!=-1 test is made *before* the user enters
the gal value, so you have to proceed to the end of the loop before the loop
finishes. You don't actually have to enter -1 under both gallons and miles.
After you enter -1 for gal, you can enter anything for miles and the loop
will still end. You could handle this in various ways. One way is to use
while(true)
{
cout << "\nEnter the gallons used (Enter -1 to finish) :\n";
cin >> gal;
if(gal == -1)
break;
// remainder of loop
}
Another way is to have the initial gallons query before the loop and all
subsequent gallons queries as the final part of the loop.
cout << "\nEnter the gallons used (Enter -1 to finish) :\n";
cin >> gal;
while(gal != -1)
{
cout << "Enter the miles driven:\n";
cin >> miles;
tg = tg + gal;
tm = tm + miles;
//calculate miles per gallon
mpg = static_cast < double > ( miles ) / gal;
cout << "The per gallon for this trip were :\n" << setprecision ( 6 ) <<
fixed << mpg;
cout << "\nEnter the gallons used (Enter -1 to finish) :\n";
cin >> gal;
}
Finally, you could always have one run of the while loop and then ask the
user at the *end* of the loop if they want to continue or quit and use the
answer to set the variable on which your while() condition depends (e.g.,
you could define a bool keepGoing which you initialise to true and set to
false when the user indicates they want to quit, and use while(keepGoing)).
cout << "Enter the miles driven:\n"; cin >> miles;
tg = tg + gal; tm = tm + miles;
//calculate miles per gallon mpg = static_cast < double > ( miles ) / gal;
cout << "The per gallon for this trip were :\n" << setprecision ( 6 ) << fixed << mpg; }
if ( gal != 0 ) total = static_cast < double > ( tm ) / tg; cout << "\nThe overall average was:\n"; cout << total;
Since you are dividing by tg, I think you should be testing tg!=0, not
gal!=0. You also probably want all three lines in a block, i.e.,
if ( tg != 0 )
{
total = static_cast < double > ( tm ) / tg;
cout << "\nThe overall average was:\n";
cout << total;
} ;return 0;
What is the ; at the start of the line for? }
--
John Carson
you guys are the best, saved me from a couple hour nightmare! i apologize
for the lack of etiquette, as i mentioned i'm new to this. look forward to
talking with ya in the future.
Eric Whittaker wrote: Hey thanks larry, the use of (for) is very helpful there. I'm just trying to learn here, cause my assignment wants me to use a (while) structure to accomplish this task, is this possible, when i try it keeps giving me a "undeclared identifier - gal" error.
Thanks for all your help.
'while(1)' or 'while(true)'
--
Anti-spam address, change each 'X' to '.' to reply directly.
"Eric Whittaker" <ew****@adelphia.net> skrev i en meddelelse
news:4s********************@adelphia.com... Hey thanks larry, the use of (for) is very helpful there. I'm just trying to learn here, cause my assignment wants me to use a (while) structure to accomplish this task, is this possible, when i try it keeps giving me a "undeclared identifier - gal" error.
Thanks for all your help.
Probably a
do
{
....
} while (gallons > 0)
could be appropriate.
/Peter This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics
by: Dave |
last post by:
After following Microsofts admonition to reformat my system before doing a
final compilation of my app I got many warnings/errors upon compiling an rtf
file created in word. I used the Help...
|
by: Tom |
last post by:
A question for gui application programmers. . .
I 've got some GUI programs, written in Python/wxPython, and I've got
a help button and a help menu item. Also, I've got a compiled file
made with...
|
by: wukexin |
last post by:
Help me, good men. I find mang books that introduce bit "mang header
files",they talk too bit,in fact it is my too fool, I don't learn it, I have
do a test program, but I have no correct doing...
|
by: Colin J. Williams |
last post by:
Python advertises some basic service:
C:\Python24>python
Python 2.4.1 (#65, Mar 30 2005, 09:13:57) on
win32
Type "help", "copyright", "credits" or "license" for more information.
>>>
With...
|
by: Corepaul |
last post by:
Missing Help Files
When I enter "recordset" as the keyword and search the Visual Basic Help index,
I get many topics of interest in the resulting list. But there isn't any
information available...
|
by: Steve |
last post by:
I have written a help file (chm) for a DLL and referenced it using Help.ShowHelp
My expectation is that a developer using my DLL would be able to access this help file during his development time...
|
by: Mark |
last post by:
I have loaded Visual Studio .net on my home computer and my laptop, but my
home computer has an abbreviated help screen not 2% of the help on my laptop.
All the settings look the same on both...
|
by: JonathanOrlev |
last post by:
Hello everybody,
I wrote this comment in another message of mine, but decided to post it
again as a standalone message.
I think that Microsoft's Office 2003 help system is horrible, probably...
|
by: trunxnirvana007 |
last post by:
'UPGRADE_WARNING: Array has a new behavior. Click for more: 'ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?keyword="9B7D5ADD-D8FE-4819-A36C-6DEDAF088CC7"'
'UPGRADE_WARNING: Couldn't resolve...
|
by: hitencontractor |
last post by:
I am working on .NET Version 2003 making an SDI application that calls MS Excel 2003.
I added a menu item called "MyApp Help" in the end of the menu bar to show Help-> About.
The application...
|
by: ryjfgjl |
last post by:
ExcelToDatabase: batch import excel into database automatically...
|
by: Vimpel783 |
last post by:
Hello!
Guys, I found this code on the Internet, but I need to modify it a little. It works well, the problem is this: Data is sent from only one cell, in this case B5, but it is necessary that data...
|
by: jfyes |
last post by:
As a hardware engineer, after seeing that CEIWEI recently released a new tool for Modbus RTU Over TCP/UDP filtering and monitoring, I actively went to its official website to take a look. It turned...
|
by: ArrayDB |
last post by:
The error message I've encountered is; ERROR:root:Error generating model response: exception: access violation writing 0x0000000000005140, which seems to be indicative of an access violation...
|
by: PapaRatzi |
last post by:
Hello,
I am teaching myself MS Access forms design and Visual Basic. I've created a table to capture a list of Top 30 singles and forms to capture new entries. The final step is a form (unbound)...
|
by: Defcon1945 |
last post by:
I'm trying to learn Python using Pycharm but import shutil doesn't work
|
by: af34tf |
last post by:
Hi Guys, I have a domain whose name is BytesLimited.com, and I want to sell it. Does anyone know about platforms that allow me to list my domain in auction for free. Thank you
|
by: Faith0G |
last post by:
I am starting a new it consulting business and it's been a while since I setup a new website. Is wordpress still the best web based software for hosting a 5 page website? The webpages will be...
|
by: isladogs |
last post by:
The next Access Europe User Group meeting will be on Wednesday 3 Apr 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM).
In this session, we are pleased to welcome former...
| |