Why is my formula not working ?

[danzal]

My fahrenheit doeesnt work

#include <iostream>
using namespace std;

int main ()

{
	int celsius, Fahrenheit;
	cout << "Enter temperature in Celsius : " ;
	cin >> celsius ;
	Fahrenheit = 9/5*celsius+32 ;

	cout << " Temperature in Celsius " << "\t\t" << " Temperature in Fahrenheit " << endl;
	cout << "\t\t\t\t" << celsius << "\t\t\t\t\t" << Fahrenheit << endl;
			 system("pause");
	    return 0;
}

[eyenrique]

Hi @danzal
i do not know if
the formula is correct
(google knows) but
i suppose that you are not
getting decimal precision;

Use double types (objects),
variables etc;
or convert temporarily one
of your integers i.e.

int total=4;
int sum=20;
double average=static_cast<double>(sum)/total;

regards!

[danzal]

hi i do not want a decimal answer the answer should be 91 minus the decimal but i get a 65 is there anything wrong ?

[eyenrique]

Yes, "order"
try this:

Fahrenheit = ((9/5)*celsius)+32 ;

EDIT: The order (C++ operator precedence) seems to be ok even without parentheses;

[keskiverto]

Integer division discards remainder. Therefore, 9/5 equals 1 and thus your equation is effectively F=C+32.

If you had written 9.0/5, which has double/int -- which in turn converts to double/double before evaluation -- then you would have floating point division (and both celsius and 32 would convert to doubles before multiplication and addition).

Assignment to integer does discard the fraction too.

[eyenrique]

I googled the formula and
entering 37 celsius using
your program i got 69

#include <iostream>
using namespace std;

int main ()

{
        int celsius, Fahrenheit;
        cout << "Enter temperature in Celsius : " ;
        cin >> celsius ;
        Fahrenheit = 9/5*celsius+32 ;

        cout << " Temperature in Celsius " << "\t\t" << " Temperature in Fahrenheit " << endl;
        cout << "\t\t\t\t" << celsius << "\t\t\t\t\t" << Fahrenheit << endl;
                         system("pause");
            return 0;
}

---
Enter temperature in Celsius : 37
 Temperature in Celsius 		 Temperature in Fahrenheit 
				37					69

[eyenrique]

as @keskiverto said
"Integer division discards remainder"
so, try this;

#include <iostream>
using namespace std;

int main ()

{
        int celsius, Fahrenheit;
        cout << "Enter temperature in Celsius : " ;
        cin >> celsius ;
        Fahrenheit = 1.8*celsius+32;

        cout << " Temperature in Celsius " << "\t\t" << " Temperature in Fahrenheit " << endl;
        cout << "\t\t\t\t" << celsius << "\t\t\t\t\t" << Fahrenheit << endl;
                         system("pause");
            return 0;
}

[giblit]

Well yeah..37+32 = 69.
The correct answer should be 98.6 or 98 since he wants integer.

Look at keskiverto's post. They show the problem which is integer division the OP wants floating point division.

[eyenrique]

Well @danzal in resume:

Fahrenheit = 9/5*celsius+32;

We found that:

1)Your formula it's right!
2)The "order" or precedence operators
are right!
3)"Integer division discards remainder"
So, 9/5 =1; (instead of 1.8)
Then: (one times C)1*C = C; (celsius)
WrongAnswer=C+32;


EDIT: constant 32;