Division operation not giving the right result

Question

i'm having a problem with this operation that is not really giving the right result. The result is 60216 on terminal, but it should be 563376.

int a = 8536;
int b = 563376;
int d = 8536;
unsigned long long int k = (a*b);
cout << k/d << endl;

it doesn't matter than k is `long`. a and b are both `int` so it generates a signed 32 bit result and THEN assigns it to the long. Your long storage is too late — Garr Godfrey, Feb 16 '22 at 00:24

pm100 · Accepted Answer · 2022-02-16T00:30:47.807

1

you need long long everywhere

long long int a = 8536;
long long int b = 563376;
long long int d = 8536;
unsigned long long int k = (a * b);
std::cout << k / d << std::endl;

note that its nothing to do with division. THis

int a = 8536;
 int b = 563376;
unsigned long long int k = (a * b);
std::cout << k  << std::endl;

gives the wrong answer too

edited Feb 16 '22 at 00:30

answered Feb 16 '22 at 00:28

pm100

I tryed to put only b as long long int and it worked. Do you know why ? – Leonardo Feb 16 '22 at 00:30
@Leonardo https://stackoverflow.com/questions/46073295/implicit-type-promotion-rules – pm100 Feb 16 '22 at 00:31
@Leonardo summary: types get promoted to the longest one in a given operation. SO having one long long in a calculation promotes them all to long long – pm100 Feb 16 '22 at 00:32
Oh, thanks! I Have spent so much time trying to fix that. You helped me a lot. Thanks again. – Leonardo Feb 16 '22 at 00:35

1 Answers1