Float prints Int in C

Question

I am beginner at programming and I am just writing a very simple program to return the solution of 23/5. My code is below:

float res  = 23/5;
printf("%.3f", res);

The expected answer is 4.6, however, the code outputs: 4.000.

`23/5` is an integer division and the result is an `int`. You want `23.0/5`. — Jabberwocky, Jan 18 '21 at 15:42
So for division in you must input your operands as floats even if they are whole numbers? @Jabberwocky — Albert, Jan 18 '21 at 15:44
@Albert yes. At least one of the operands must be a floating point number. — Jabberwocky, Jan 18 '21 at 15:44
Unrelated: prefer `double` when dealing with floating-point values. — pmg, Jan 18 '21 at 15:45
Why is this necessary? As in why doesn't it automatically realise that it shouldn't be output as integer? Sorry I am very new at this. @Jabberwocky — Albert, Jan 18 '21 at 15:46
@Albert an `int` divided by and `int` is an `int`. These are the rules of the language and this is a very good rule. You don't want your `int`s automatically be transformed into a floating point value (which one BTW, there is `float` and `double`). — Jabberwocky, Jan 18 '21 at 15:50
@Jabberwocky, yes that makes sense, thank you for the explanation. — Albert, Jan 18 '21 at 15:52
Adding to that, the language does not consider the target type until *after* the computation. — Weather Vane, Jan 18 '21 at 16:09
@WeatherVane is this a C thing or is this true for all compiled languages? — Albert, Jan 18 '21 at 16:27
I don't know *all* compiled languages and it is better not to make assumptions. — Weather Vane, Jan 18 '21 at 16:45

mitchell · Answer 1 · 2021-01-18T16:12:15.227

0

You are setting its value to an int

float res  = 23.0f/5.0f;
printf("%.3f", res);

edited Jan 18 '21 at 16:12

answered Jan 18 '21 at 15:42

mitchell

1

to divide float numbers you need to `23.0f/5.0f` otherwise it will be double division – 0___________ Jan 18 '21 at 15:52

1 Answers1