simple pi calculating program

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FEARmike21 FEARmike21 is offline Offline
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simple pi calculating program

 
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  #1
Feb 22nd, 2009
Hi, I just started my C++ class a couple weeks ago and I am stuck and having a really diffcult time understanding which commands to use in my programs. I don't even know where to look to get a list.

Anyways, basically what we have to make our program do is take an imput from the user asking "Enter radius of circle:" and with that radius calculate and output the area on the screen and reiterate what the user typed in.

Here is my source code:
C++ Syntax (Toggle Plain Text) 
  1. #include <iostream>
  2. #include <cmath>
  3.  
  4. using namespace std;
  5.  
  6. int main (int argc, char *argv[], char **env)
  7. {
  8.  
  9. cout << "Enter radius of circle:";
  10. double r = cin.get;
  11. double a = ( r * M_PI ) * ( r * M_PI );
  12.  
  13. cout << "Area is:" << a << "for radius of:" <<  r << ;
  14.  
  15. return 0;
  16.  
  17.  
  18. }
I am getting all sorts of errors and I think im on the right track I am just unsure of how exactly to type it out.

Any input would be greatly appreciated.
Last edited by Ancient Dragon; Feb 22nd, 2009 at 5:47 pm. Reason: add code tags
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Re: simple pi calculating program

 
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  #2
Feb 22nd, 2009
Code tags:


[code]
// paste code here
[/code]


C++ Syntax (Toggle Plain Text) 
  1. double r = cin.get;

http://www.cplusplus.com/reference/i...tream/get.html

If this is a function call, you need parentheses.
C++ Syntax (Toggle Plain Text) 
  1. double r = cin.get;
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Re: simple pi calculating program

 
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  #3
Feb 22nd, 2009
C++ Syntax (Toggle Plain Text) 
  1. cin.get (r);

instead of
C++ Syntax (Toggle Plain Text) 
  1. double r = cin.get;

?
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Re: simple pi calculating program

 
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  #4
Feb 22nd, 2009
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Originally Posted by FEARmike21 View Post
C++ Syntax (Toggle Plain Text) 
  1. cin.get (r);

instead of
C++ Syntax (Toggle Plain Text) 
  1. double r = cin.get;

?
When in doubt, try it and find out for sure, which I imagine you have. The link I posted has specs and examples. None of them take a double as a paremeter. I don't see any reason for you to use get here. Just use cin .
C++ Syntax (Toggle Plain Text) 
  1. double r;
  2. cin >> r;
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Re: simple pi calculating program

 
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  #5
Feb 23rd, 2009
I agree with, VernonDozier.
cin>> is already overloaded for you to input the right thing.
cin.get is a unformated input function. It does not format the input accordingly. It is just used for char
heres the prototype
C++ Syntax (Toggle Plain Text) 
  1. get ( char* s, streamsize n );
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Re: simple pi calculating program

 
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  #6
Feb 23rd, 2009
The last << causes trouble.
C++ Syntax (Toggle Plain Text) 
  1. cout << "Area is:" << a << "for radius of:" <<  r << ;

Remove it.
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Re: simple pi calculating program

 
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  #7
Feb 23rd, 2009
Hi what I would is

C++ Syntax (Toggle Plain Text) 
  1. cout<<"Please enter the radius"<<endl; //prompt the user for an input
  2. double radius; // declare the variable which will hold the radius
  3. cin>>radius; //make the user enter the radius
  4. double area=M_PI*radius*radius; // i think you used the wrong formula
  5. cout<<"user entered: "<<radius<<endl
  6.        <<"area is: "<<area;
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Re: simple pi calculating program

 
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  #8
Feb 23rd, 2009
As mentioned above cin>> is already overloaded for use so its better to use it in this case.
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