How to Calculate Grams to Ounce and Pounds

[siabapet]

Convert grams to ounces and pounds, if 1 ounce = 28,3495 gram and 1 Pound = 12 Ounce.
If anyone ask why 1 pound = 12 ounce not 1 pound = 16 ounce, yes its wrong but the question is like that.

  #include<iostream>
using namespace std;

int main()
{
	float ..........

Thanks in Advance

[salem c]

This is a math problem first, then a programming problem.

If I ask you to convert 54145 grams to pounds and ounces, using only pen and paper, could you do it?

You need to be able to do this much before you even think about writing the code.

[againtry]

#include<iostream>

using namespace std;

int main()
{
    double wt_in_grams{0};
    cout << "How many grams: ";
    cin >> wt_in_grams;

// convert g to oz ...

// convert oz to lb ...

    return 0;
}

BTW I know what europeans do with commas but are you sure 1 oz = 283.495 kg because that's what it says?
1 oz = 28.3495g, and 1 lb = 16 oz
OR,
1g = 1/28.3495 oz, and 1 oz = 1/16 lb

[jonnin]

regardless of the numbers, just make constant doubles, eg
const double oztog=28.35;
and so on...
then its just a multiply.
...
cout << "5 oz is " << 5*oztog << " grams";

you can use the wrong info for the problem, whatever, it still becomes a constant for each conversion.

[Handy Andy]

Hello siabapet,

I would start with salem c's suggestion of working out what you need on paper first. This makes writing the code much easier.

Then to go along with what jonnin has said consider this as a start:

#include <iostream>
#include <iomanip>  // <--- For "std::fixed", "std::showpoint" and "std::setprecision".
#include <limits>

int main()
{
    constexpr double GRAMS{ 28.34952 };  // <--- Can use whatever number you like.
    constexpr double POUNDS{ 16 };       // <--- Can be changed later.

    double weightInGrams{};

    std::cout << std::fixed << std::showpoint << std::setprecision(4);  // <--- Used later when displaying floating point numbers.

    std::cout << "\nEnter the weight in grams: ";
    std::cin >> weightInGrams;

    //while (std::cout << "\nEnter the weight in grams: " && !(std::cin >> weightInGrams))
    //{
    //    std::cerr << "\n     Invalid entry! Must be a number.\n";

    //    std::cin.clear();
    //    std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');  // <--- Requires header file <limits>.
    //}

    std::cout << "\n You entered: " << weightInGrams << '\n';


    // <--- Keeps console window open when running in debug mode on Visual Studio. Or a good way to pause the program.
    // The next line may not be needed. If you have to press enter to see the prompt it is not needed.
    std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');  // <--- Requires header file <limits>.
    std::cout << "\n\n Press Enter to continue: ";
    std::cin.get();

    return 0;  // <--- Not required, but makes a good break point.
}

Prefer to use "double"s over "float"s.

An example: " 28.34952" is likely to be stored as "28.34951999999999828". When displayed it will round up properly, but in a calculation it will be a bit short. And compared to a "float" "28.34951973". You can see there is a difference in the numbers and your calculations will come out differently.

For line 8. I know that you said you need to use 12, but get the program working correctly first. You may find a sue for it later. After the program is running you can later change the "16" to "12" before you turn it in.

The commented while loop is a better way of dealing with formatted input in case you enter something that is not a number. Either one will work.

Line 25 is for testing. You do not have to keep this.

Andy