My first project (need insight from regular users)

[xander333]

Hello everybody,

I'm new to these forums and also to C++. I started experimenting a bit yesterday and today i made my first *useful* program. It is a BMI calculator.I know it is in dutch, but that shouldn't change the behavior of the program (I think?).

I would like to know if I programmed unnecessary parts or if I could do it easier/cleaner.

Thanks in advance!

//operating with variables

#include <iostream>

using namespace std;

int main () 
{
    //declaring variables
    float a,b ;
    float result ;
    
    //process
    cout<< "geef je gewicht op \n";
    cin>> a;
    cin.ignore ();
    cout<< "geef je lengte op in meter \n";
    cin>> b ;
    cin.ignore ();
    
    result = a / (b*b);
    //result
    if (result < 17.5) {
               cout<< "Je BMI is "<< result <<". Je hebt ondergewicht.";
               }
    else if (result < 24.99) {
         cout<< "Je BMI is "<< result <<" . Je bent normaal.";
         }
    else if (result < 29.99) {
         cout<< "Je BMI is "<< result <<" . Je hebt overgewicht.";
         }
    else if (result > 29.99) {
         cout<< "Je BMI is "<< result <<" . Je hebt ernstig overgewicht. Laat je testen op Obesitas.";
         }
    cin.get ();
}
    

[m4ster r0shi]

Hello to you too. Nice one, well done! :D Most people declare their variables as ints and then have trouble with the division operation, but it seems that you haven't fallen to this trap. I have a few suggestions though:

#include <iostream>
using namespace std;

//make a string table with the bmi descriptions
const char * bmi_description[]=
{"Je hebt ondergewicht.","Je bent normaal.",
"Je hebt overgewicht.","Je hebt ernstig overgewicht."
" Laat je testen op Obesitas."};

int main ()
{
    //declaring variables
    float a,b ;
    float result ;

    //process
    cout<< "geef je gewicht op \n";
    cin>> a;

    //cin.ignore (); //<- this will only ingore one char
    //I usually do it like this:
    while(cin.get()!='\n');

    cout<< "geef je lengte op in meter \n";
    cin>> b ;

    //cin.ignore (); //same here
    while(cin.get()!='\n');

    //result
    result = a / (b*b);

    //declare a variable to hold the bmi class
    //and set its value depending on the result
    int bmi_class;

    if (result < 17.5) bmi_class=0;
    else if (result < 24.99) bmi_class=1;
    else if (result < 29.99) bmi_class=2;
    else /*if (result > 29.99) (<-you can omit this)*/ bmi_class=3;

    //print the results
    cout<< "Je BMI is "<< result <<" . " << bmi_description[bmi_class];

    cin.get ();
    return 0;
}

[xander333]

Thanks M4ster, that's a really helpful post, however I don't get what

while (cin.get () !='\n'

means.

And why const char * bmi_description[]=?

Help please!

[crazzyguy101]

Thanks M4ster, that's a really helpful post, however I don't get what

while (cin.get () !='\n')

Maybe this will help you.
http://www.cplusplus.com/reference/iostream/istream/ignore/

And why const char * bmi_description[]=?

He used a pointer to a character array to store the descriptions. You can also use a string array and it is much easier. But dont forget to use use #include<string>

std::string[] =  {"Je hebt ondergewicht.","Je bent normaal.",
"Je hebt overgewicht.","Je hebt ernstig overgewicht."
" Laat je testen op Obesitas."};