Multiplication of three numbers in c give a wrong results?

Question

I can\'t belive what\'s happen in my program

double den = 180*3600*10000 ;

in debugging a got this value -2109934592.0000000

any he

Answer 1

With the full code in the question we can now see it's an integer overflow.

10000 * 180 * 3600 = 6,480,000,000.

This is greater than 2,147,483,648 which is the max value of a 32-bit signed int. The results of the multiplication overflows to -2,109,934,592 and is then converted to double.

To get the right result make one of the numbers a double before you do the multiplication:

10000.0 * 180 * 3600

Answer 2

test.c: In function ‘main’:
test.c:6:37: warning: integer overflow in expression [-Woverflow]
      double denominator =  10000*180*3600 ;
                                     ^

Is the error when I compile. Your overflowing ints and casting to a double.

   double denominator =  10000.0*180.0*3600.0 ;

Fixes the issue