c++ double doesn't work

Question

Why in c++ double doesn't work if I write:

int a, b;
double c;

a=11;
b=2;
c=a/b;

right answer according to me should be 5,5 but it writes just 5 anyone knows how to fix this?

because int/int = int, so do a*1./b, or (double)a/b, or C++ way `static_cast(a)/b;` — Creris, Feb 03 '15 at 19:29
Check this topic: http://stackoverflow.com/questions/28256829/c-program-why-does-this-array-have-this-output/28256899 — myaut, Feb 03 '15 at 19:30
C++ doesn't look at the type of the result when it does the calculation, it performs the calculation based on the types of the operands (which are both integer) and *then* converts the result. You fix it by making sure one of the operands *isn't* int. — Mark Ransom, Feb 03 '15 at 19:30

score 3 · Answer 1 · answered Feb 03 '15 at 19:31

3

A division of an int by another int yields an int. This occurs before the quotient is assigned to the double variable.

To fix this, cast at least one of the int values to a double. In other words, change this:

c=a/b;

to this:

c = static_cast<double>(a) / b;

answered Feb 03 '15 at 19:31

Spire

And if `static_cast` is too wordy for you, a quick way to get a double from an int is addition: `(a+0.0)`. – Mark Ransom Feb 03 '15 at 19:35

score 0 · Answer 2 · answered Feb 03 '15 at 19:31

0

a must be double too, or float

double a,b,c;

That'll work

answered Feb 03 '15 at 19:31

ForceBru

2 Answers2