Is there any way to add passing-by-reference to this code? - c++

Question

Student here. I'm missing a single rubric item in the following project program and can't figure out where to place it, "it" being a pass-by-reference item. If anyone is feeling generous, please take a look at my program below and give me a heads-up about where I could tweak the code to make pass-by-reference possible. As it stands, I'm stumped and I don't have enough time to come up with an entirely new problem for which to code a solution. Thank you all in advance!
#include <iostream>
#include <cmath>
using namespace std;
//Global Variable
int height = 0;
//Function Prototypes
int getMale();
int getFemale();
int main()
{
//Local Variable
int ideal = 0;
char sex(' ');
//Sequence Structure
cout << "Welcome to the Hamwi Ideal Body Weight Equation Calculator!" << endl;
cout << "Please enter your height in inches (remember, 1 foot = 12 inches): " << endl;
cin >> height;
cout << "Please enter your biological sex (M or F): " << endl;
cin >> sex;
//Repetition Structure
while (toupper(sex) != 'M' && 'F')
{
cout << "Invalid entry. Please enter your biological sex (M or F): " << endl;
cin >> sex;
} //end while
//Selection Structure
if (toupper(sex) == 'M')
{
int ideal = getMale();
cout << "Thank you. Your ideal body weight is approximately: " << ideal << " pounds." << endl;
cout << "Have a nice day!" << endl;
} //end if
else
{
int ideal = getFemale();
cout << "Thank you. Your ideal body weight is approximately: " << ideal << " pounds." << endl;
cout << "Have a nice day!" << endl;
} //end else
return 0;
} //end of main function
//Program-Defined Function #1 (Male)
int getMale()
{
//Local Variable
int male = 0;
if (height >= 60)
{
male = 106 + ((height - 60) * 6);
return male;
} //end if
else
{
male = 106 - ((60 - height) * 6);
return male;
} //end else
} //end of male function
//Program-Defined Function #2 (Female)
int getFemale()
{
//Local Variable
int female = 0;
if (height >= 60)
{
female = 100 + ((height - 60) * 5);
return female;
} //end if
else
{
female = 100 - ((60 - height) * 5);
return female;
} //end else
} //end of female function

Answer 1

Declare your two functions like this
int getMale ( int& height );
int getFemale ( int& height );
And in your main you declare a variable that you can pass to the functions
int main()
{
// Declare here instead of globally
int height = 0;
// Then you can call
int result = getMale(height);
result = getFemale(height);
}
It will behave the same way. It is considered better practice to pass by reference than to use a global variable, so kudos to you for asking this question.

Answer 2

You pass height by reference in one of your gender functions.
For example:
int getMale(int &height) {
/* do stuff */
}
And then simply call it by:
getMale(height);
Also, are you required go use a global variable? If not, then make height a local variable in your main as other commenters have stated. Global variables are considered bad style, as they can cause hard-to-diagnose problems when you're working on a much larger project.

Answer 3

You could move variable height to main() (make it local) and pass it by reference to all your functions. Actually, I'd say that would be a better style than passing data through global variables.
But in a real project it's typically better to think of what behavior you want from your program, not of what awesome language features you want to use.

Answer 4

Is this program not giving you the correct answer and that's why you want to pass by reference? or what is the exact situation?
Anyways in order for you to pass by reference then you remove height from being a global variable and have it local in your main, then for your prototypes include a reference parameter then when you call them in main pass your local variable.
This is example of how pass by reference would work.
#include<iostream>
using namespace std;
//Prototype
void add(int num1, int num2, int &res);
int main()
{
int res;
add(1, 2, res);
cout<<"I got the value by passing my variable by reference"<<res<<endl;
return 0;
}
void add(int num1, int num2, int &res)
{
res = num1 + num2;
}