do while question

[Vanilla_Rice]

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???

[ProgramArtist]

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

[Vanilla_Rice]

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

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 );

[ProgramArtist]

*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

[LOOSER_007]

while ( number >= 2.5 & <= 6.5 );

[/code]

&- Bitwise AND operation
&&- Logical AND operation.
Replace with this- while ( (number >= 2.5) && (number<= 6.5) );

Refer some programming books to improve your basics....

[Vanilla_Rice]

thanks loser 007

can anyone point me in the direction of a good free C compiler?

[ovidiucucu]

can anyone point me in the direction of a good free C compiler?

Visual C++ Express Edition.

[GCDEF]

Replace with this- while ( (number >= 2.5) && (number<= 6.5) );

I'd omit the superfluous parentheses myself.

[krmed]

Since you want to stay in the loop until a number is within the range, you need to change

while ( (number >= 2.5) && (number<= 6.5) );

to this

while ( (number <= 2.5) || (number>= 6.5) );

Hope that helps.

[LOOSER_007]

Since you want to stay in the loop until a number is within the range, you need to change

while ( (number >= 2.5) && (number<= 6.5) );

to this

while ( (number <= 2.5) || (number>= 6.5) );

Hope that helps.

I don't Think so.. e.g. What if number = 1.0
so While((1.0<2.5 is = TRUE || (Anything)) = TRUE) so the loop still goes on...

[GCDEF]

I don't Think so.. e.g. What if number = 1.0
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.

[Vanilla_Rice]

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?

[LOOSER_007]

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.

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...
while ( (number <= 2.5) || (number>= 6.5) );

Best Regards

[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?

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....

[Vanilla_Rice]

ahh thats good to know, to be honest i didnt read krmed's post correctly eigther..