[Tutor] small program in Python and in C++

[Rob]

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Quite right. Attached is a C++ source file with the formula wrapped in a 
function.

Another friend contributed this equivalent (but not with the function) 
version in Perl:


#!/usr/bin/perl

print "What is your height in inches? ";
$inches=<STDIN>;
print "What is your weight in pounds? ";
$pounds=<STDIN>;

$bmi= 703 * ($pounds/($inches*$inches));

print "Your body mass index is $bmi\n";

if ($bmi>=30) { print "You are obese!\n"; }
else { print "You are not obese!\n"; }


Happy Hacking,
Rob
http://uselesspython.com

Danny Yoo wrote:

> 
> On Tue, 2 Jul 2002, Rob wrote:
> 
> 
>>I thought I'd pass it all along to the Tutor list in case it makes a
>>good example for anyone (or if anyone cared to point out other ways to
>>do it, etc.). If you know a little C++ and are looking into Python, or
>>vice versa, you might like it on some level.
>>
>>
>># calculate body mass index
>>bodyMassIndex = 703 * ( weight / ( height * height ) )
>>
> 
> It might be good to make this a function --- even though it's so simple,
> having it as a function makes it easy to reuse this calculation if we ever
> need it later.  As an additional bonus, if we write it as a function, we
> can play with it very easily within the interactive interpreter:
> 
> 
> ###
> 
>>>>def bodyMassIndex(weight, height):
>>>>
> ...     return 703 * ( weight / ( height * height ) )
> ...
> 
>>>>bodyMassIndex(175, 6.5)
>>>>
> 2911.834319526627
> 
>>>>bodyMassIndex(175, 6)
>>>>
> 2812
> ###
> 
> 
> Oh!  It also reveals that we need to be careful about the types that we
> use to do the calculation when division comes into play.
> 
> 
> C++'s variable typing forces weight and height to be floats, but we don't
> restrict the same in Python. If "from __future__ import true_division"
> isn't on, we should probably force floating point division:
> 
> ###
> 
>>>>def bodyMassIndex(weight, height):
>>>>
> ...     return 703 * ( weight / float( height * height ) )
> ...
> 
>>>>bodyMassIndex(175, 6)
>>>>
> 3417.3611111111109
> ###
> 
> 
> Hope this helps!
> 
> 
> 
> _______________________________________________
> Tutor maillist  -  Tutor@python.org
> http://mail.python.org/mailman/listinfo/tutor
> 
> 


-- 
"Giving the Linus Torvalds Award to the Free Software Foundation is a 
bit like giving the Han Solo Award to the Rebel Alliance."
--Richard Stallman at the 1999 LinuxWorld show

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#include <iostream>
using namespace std;

// function prototype for getBMI()
// A function prototype appearing before the function is called
//     in a program tell the program how to talk to the function.
float getBMI(float, float);

int main()
{
    // fetch data from the user
    cout << endl << "What is your height in inches? ";
    float height;
    cin >> height;
    cout << endl << "What is your weight in pounds? ";
    float weight;
    cin >> weight;
    
    // calculate body mass index
    float bodyMassIndex;
    bodyMassIndex = getBMI(height, weight);
    
    // display obesity judgement
    cout << "\nYour Body Mass Index is " << bodyMassIndex << endl;
    if (bodyMassIndex >= 30)
        cout << "\nYou are obese." << endl;
    else
        cout << "\nYou are not obese." << endl;
        
    return 0;
}

//---------------------------------------------------------------
// In this function, "height" could just as easily read "inches",
//     and "weight" could just as easily read "pounds"
//     without having to change anything outside the function.
//     Just a handy fact for those who are new to C++.
float getBMI(float height, float weight)
{
    return 703 * ( weight / ( height * height ) );
}

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