How to use modulo????

[BEARS]

I am very new to programming and I'm struggling with understanding modulo. I get that it means remainder, but I am having trouble using it in an actual program. Here is a ounces to pounds converter. the goal is to input a number of ounces and convert that to pounds with a remainder of ounces.

#include<iostream>

using namespace std;

int main(void)

    {
        
        cout <<"\n\t\tWelcome to the Converter Calculation Propgram!\n";
        
               unsigned short ounces, pounds, ounces_left;
        
               const ounces_per_pound = 16;
            
        cout<<"\nHow many ounces do you have?";
        
                cin>> ounces;
                
                cin.ignore(INT_MAX, '\n');
                
        cout<<"\nThank you!";
            
        cout<<"\nCalculating...\n";
            
            
                   // How do I setup the equation here???
            
        cout<<"\nDone.\n";
            
            

[YFGHNG]

#include<iostream>

using namespace std;

const int OUNCES_PER_POUND = 16;

int main( void )
{
    unsigned int ounces, pounds, ounces_left;
    cout << "Welcome to the Converter Calculation Program!" << endl;
    cout << "How many ounces do you have? ";

    cin >> ounces;
    cin.ignore(999, '\n');
  
    cout << "Thank you!" << endl << "Calculating..." << endl;

    pounds = ounces / OUNCES_PER_POUND;
    ounces_left = ounces % OUNCES_PER_POUND;

    if( pounds == 1)
        cout << "You have " << pounds << " lb with "<< ounces_left << " ounces leftover." << endl;
    else
        cout << "You have " << pounds << " lbs with "<< ounces_left << " ounces leftover." << endl;
}

Some explanation on the code:

Line 18 - since we're using integer type variables, integer division will not have decimals, aka floats, doubles, long, etc. This gives us a nice whole number to work with when we're trying to figure out how many pounds we have.

Line 19 - modular arithmetic is basically what we all learned in elementary school. Just take out groups of x from a number y, and see what's left over. For example, if I have 33 oz. How many groups of 16 are in 33? Only 2. So you do 23 - 16*2 = 1. And there is your remainder.

[BEARS]

Ok that part makes a bit more sense now. What did you do in lines 21-24? I didn't learn much about if else statements yet. Can you explain what is happening in those lines? What does it do for the program? what does the ( pounds == 1 ) do exactly? etc.

[YFGHNG]

That's a preference thing. Because when I wrote it up earlier, I was testing it with a few numbers and the first number I typed in was 23. What printed out was "You have 1 lbs with 7 ounces leftover". Grammatically, that's incorrect. So I added an if else to check for when the # of pounds equaled 1.

If it's still kind of confusing for you, think about it this way:
How would you say $0? What about $1? $100? $5? Mind you, this is in English, not another language.

Also in C++ you're gonna have to distinguish between = and ==.

= is assignment. That is, you're giving a variable an exact value.
Ex. int a; a = 15; // you have now given variable a the value of 15;

== is equality. It return a boolean, meaning you HAVE to have two sides to compare.
Ex. int a; a = 15; int b; b = 20; /* b == a */ // this returns false, because 15 is NOT equal to 20

[BEARS]

ohhhhhh. Ok cool. This makes a lot more sense now. THANKS!!!!

[BEARS]

I tried compiling mine but I got some errors that I'm not sure how to fix. How is there no type in line 21 when I used const? and why do i need a ";" in the middle of a sentence in 38???

ERRORS:

convert.cpp: In function `int main()':
convert.cpp:21: error: ISO C++ forbids declaration of
`ounces_per_pound' with no type
convert.cpp:38: error: expected `;' before "ounces_left"

[YFGHNG]

Check your positions of your quotation marks "" in line 39.

Const is used to modify an object type, in this case, making your ounces_per_pound immutable. Now ask yourself this: what is the type of ounces_per_pound?

[BEARS]

Oh. I got it. I used const short and it worked. Thanks! Can you explain a bit more what const does exactly to the data type? What do you mean by "Const is used to modify an object type"? How does it modify it?

[YFGHNG]

There's several usages of const, some which will seem extremely confusing for you. But don't worry about it for now. Here's a good reference for you if you ever feel confused.

http://duramecho.com/ComputerInformation/WhyHowCppConst.html

[BEARS]

Hmm. Very interesting. and weird :/. Anyway thanks again for all the help and clarification!