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I have to use the "do while" statement for the following question in my programming class:
Prompt for a number between 2.5 and 6.5 (loop until a number is correctly inputted)
If the number is outside the specified range, display an error message and ask for another number.
Help needed thankyou. I dont know how to write this???
Hi,
You don't know how to write this?
If someone will do it for you you won't learn anything.
Please write what you have so far and where your problem is!
And refer to the Before you post section and the FAQ's first!
With regards
Programartist
ok sorry here is what I have done already, I am not sure if what I have put in the while bracket is correct, also I am unsure how to go about displaying the error message and asking for another number.. I have searched through my text book but its written in a way that I cant understand hence why im asking here.. thanks in advance
Code:double number;
do
{
Printf("Please enter a number between 2.5 and 6.5");
fflush(stdin);
scanf("%lg", &number);
}while ( number >= 2.5 & <= 6.5 );
*hmh*
Did you give this code any chance to compile?
There are a few errors in the code you posted.
Some will cause compiler errors.
Please try to compile this code, read the error messages the compiler will give you and try to understand what they mean.
If you can change your code so that it can be compiled without errors then please try to execute it. If the program won't do what you're expecting then use the debugger and execute it step by step.
(Of course I could tell you the errors (or at least some of them). But you should learn something, shoudn't you?)
With regards
Programartist
&- Bitwise AND operationQuote:
Originally Posted by Vanilla_Rice
&&- Logical AND operation.
Replace with this- while ( (number >= 2.5) && (number<= 6.5) );
Refer some programming books to improve your basics....:)
thanks loser 007
can anyone point me in the direction of a good free C compiler?
Visual C++ Express Edition.Quote:
Originally Posted by Vanilla_Rice
I'd omit the superfluous parentheses myself.Quote:
Originally Posted by LOOSER_007
Since you want to stay in the loop until a number is within the range, you need to changeto thisCode:while ( (number >= 2.5) && (number<= 6.5) );
Hope that helps.Code:while ( (number <= 2.5) || (number>= 6.5) );
I don't Think so.. e.g. What if number = 1.0Quote:
Originally Posted by krmed
so While((1.0<2.5 is = TRUE || (Anything)) = TRUE) so the loop still goes on...
He wants to prompt until a number is in that range. If the number is 3 for example, both conditions are false and the loop ends as required.Quote:
Originally Posted by LOOSER_007
lets say I use
while ( (number >= 2.5) && (number<= 6.5) );
I think I wrote it wrong, should'nt it be:
while ( (number < 2.5) && (number > 6.5) );
looking at the less than and greater than statements these appear to be the wrong way around to me, because if i used the first one surely if would continue to ask me to enter a number between 2.5 and 6.5 as that's how I'd interpret it.
your thoughts anyone?
Oh... Its my mistake i didn't read the question well...I was interpreting it the other way..... What krmed has written is absolutely right...Quote:
Originally Posted by GCDEF
while ( (number <= 2.5) || (number>= 6.5) );
Best Regards
while ( (number < 2.5) && (number > 6.5) ) this condition always result in FALSE as the number cannot be <2.5 and >6.5 at the same time.... What krmed has mentioned i.e use LOGICAL OR || for your while loop condition....Quote:
Originally Posted by Vanilla_Rice
ahh thats good to know, to be honest i didnt read krmed's post correctly eigther..
again, thanks for the info guys you've been a great help so far..
but to re-iterate my original question i want the program to display an error message and ask for another number if the inputted number is outside the range I ask for..
so I ask anyone who knows, how would I modify my program below to do that? thanks
Code:
#include <stdafx.h>
#include <stdio.h>
int main (void)
{
double number;
do
{
Printf("Please enter a number between 2.5 and 6.5");
fflush(stdin);
scanf("%lg", &number);
}while ( (number <= 2.5) || (number>= 6.5) );
fflush(stdin);
getchar();
return 0;
}
Hi,
Well, you've a few choices on how to use a do{}while loop for that. You need to display a different message the 2nd and subsequent times through the loop.
You could create a boolean variable, bFirstTime and initialise it as true. Then use something along the lines of
AlanCode:do
{
if (bFirstTime)
{
// set bFirstTime to false
}
else
{
// print "Sorry, that number's out of range, please try again"
}
// prompt for the number and read it as you are at the moment.
}
Are you not able to get the desired result with the code mention above.....
While loop will run until the entered number is not in your mentioned range...and will ask for other number...and goes on...
Yes I can, although this is an assignment question and I have to follow its instructions.. hence why it needs to print an error message and prompt for another number if the number isnt in the desired range..Quote:
Originally Posted by LOOSER_007
thanks for your input looser 07 and alanjhd08
STILL having problems I've emailed my lecturer who replied to me with this:
enter...
if ( condition )
action (the action is "display a clear error message and ask for another number")
It's NOT an if...else at this point, just an if.
Your "condition" is correct (I think).
so yeah, I'd prefer not to use a boolean variable at this point as we havent been taught them yet, the lecturer believes it can be done with an "If" statement although I have made a program containing one and it still doesnt work.. cant someone see any problem with what I have done below? thanks
Code:
#include <stdafx.h>
#include <stdio.h>
int main (void)
{
double number;
do
{
printf("Please enter a number between 2.5 and 6.5: ");
fflush(stdin);
scanf("%lg", &number);
if (number < 2.5) || (number > 6.5)
{
printf("Sorry that number is outside the specified range, please try again");
}
}while ( (number < 2.5) || (number > 6.5) );
fflush(stdin);
getchar();
return 0;
Not taught boolen....eh
You been wrote
if ( condition )
means condition can be true or false
in your case, your condition is that number must be in range 2.5 - 6.5
so condition is "if number smaller than 2.5 or greater than 6.5" then its some error
meaning condition in c++ is: (number < 2.5) || (number > 6.5)
so if you replace condition in if statement above, with (number < 2.5) || (number > 6.5)
you will have
if( (number < 2.5) || (number > 6.5) )
notice the plus parentheses...
if(number < 2.5 || number > 6.5)Quote:
Originally Posted by streamer
Does the same thing without the superfluous parenthesis.
you did'nt closed the if with a bracket....i.e if (number < 2.5) || (number > 6.5) should beQuote:
Originally Posted by Vanilla_Rice
if ((number < 2.5) || (number > 6.5))
I think so..... :)
Yes I know, but to explain someone who doesn't know boolean type what is precedence of operators, and why that is the same....Quote:
Originally Posted by GCDEF
Anyway I just wanted him to notice where his problem is, and to understand what is the problem. And my personal opinion is that nobody should write down that: "hey you need to add to code this 10 lines and it will work" style of posting because people who don't know really how to make a code will never learn anything, except that there are lot of users who are willing to help and do they homework.