Adding doubles in ansi C produces unexpected results

Question

For my school project we are required to do math with doubles. My current code produces some unexpected results.

/* Hello World program */

#include<stdio.h>

int main()
{

double result = 0.0;
double x;
x = 10.0;

result = x + 10.0;

printf("%d", result);

return 0;

}

Upon running, this code prints: "-1267258024"

I don't understand why this happens? Why does the code not print 20.0?

Thanks!

EDIT: I'm so dumb. %d is for floats. Thank you!

Using the wrong [`printf`](http://en.cppreference.com/w/c/io/fprintf) format leads to *undefined behavior*. — Some programmer dude, Jan 26 '17 at 05:28

score 1 · Answer 1 · answered Jan 26 '17 at 05:38

The line

printf("%d", result);

indicates that you want to print an integer.

You probably want

printf("%f", result);

There are also things like %lf (acts the same as %f) and %Lf (works for long doubles) which you can read about on this answer.

A complete list of formatting options can be found here.

Adding doubles in ansi C produces unexpected results

1 Answers1