printf - Wrong answer on a floating point number

Question

I'm trying to divide two numbers together and print the answer but the compiler always gives 1.000000 as the answer, Iv'e tried changing the literals but the answer is still the same somewhat.

Here is my code:

#include <stdio.h>
int main()
{
float a = 20 / 12;
printf ("%f", a);
}

Any ideas why this happens and how to get the right answer?

You need to learn about implicit and explicit type conversions. Only then will you understand as to why this is happening. Try doing 20/12.0 to see the difference — Vishweshwar Kapse, Sep 16 '14 at 18:25

score 4 · Answer 1 · answered Sep 16 '14 at 18:22

4

Change

float a = 20 / 12;

to

float a = 20 / 12.f;

20 / 12 is an integer division.

answered Sep 16 '14 at 18:22

ouah

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score 4 · Answer 2 · answered Sep 16 '14 at 18:25

4

typecast at least one of value as float type.

float a=(float)20/12;

answered Sep 16 '14 at 18:25

Rustam

6,485
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score 2 · Answer 3 · answered Sep 16 '14 at 18:25

2

You are performing integer division, if I change

float a = 20 / 12;

to

float a = (float) 20 / 12;

I get

1.666667

answered Sep 16 '14 at 18:25

Elliott Frisch

198,278
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Abhishek Choubey · Answer 4 · 2014-09-16T18:33:12.877

2

What you are doing is integer division, i.e.

float a = 20/12 ----- gives you the integer quotient.

In order to get a float quotient you can do it like this

float a = 20/12.0;    
or
float a = 20.0/12;

edited Sep 16 '14 at 18:33

answered Sep 16 '14 at 18:27

Abhishek Choubey

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printf - Wrong answer on a floating point number

4 Answers4