I was trying to use the formula below in c++. I have both variables declared as integers and I'm expecting them to round up but they seem to be rounding down. I have looked over this but cannot seem to find what is wrong. Any help would be greatly appreciated.
int user_degrees_latitude, user_degrees_longitude;
const int lat_const=(-90)
const int long_const=(-180)
sector_latitude = (user_degrees_latitude - lat_const) / (10);
sector_longitude = (user_degrees_longitude - long_const) / (10);
The answer should be 13 for sector_latitude and 11 for sector_longitude but the computer rounds each down to 12 and 10 respectively.
In C++, integers are not rounded. Instead, integer division truncates (read: always rounds towards zero) the remainder of the division.
If you want to get a rounding effect for positive integers, you could write:
sector_latitude = static_cast<int>(((user_degrees_latitude - lat_const) / (10.0)) + 0.5);
The addition of 0.5 causes the truncation to produce a rounding effect. Note the addition of the .0
on 10.0
to force a floating point divide before the addition.
I also assumed that sector_latitude
was an int with the casting.