double trouble

[Bj]

using

double

in c im getting weird things happening like;

double sum(double x, double y);
void run()
{
     double x,y;
     x = 5;
     y = 3;
     printf("The sum of 5 and 3 is %d\n",sum(x,y);
}
double sum(double x, double y)
{
     return x+y;
}

*note: I didnot build this to see if it actually works so just get the jist of it for now, :lol:

for something like the example above, it will return some wierd number like 42,554,654,860:blink:

But when I use int instead of double then it comes out allright, :huh:

Problem with compiler???

 

[Bj]

I figured out what I did wrong, the compiler was making double as unsigned, not signed, so in binary, thats like

0-00000000000000000000000000000001=11111111111111111111111111111111
and 32 1's in binary is a huge number. :lol:
like 2,147,483,647

double sum(double x, double y);
void run()
{
     double x,y;
     x = 5;
     y = 3;
     printf("The sum of 5 and 3 is %d\n",sum(x,y);
}
double sum(double x, double y)
{
     return x+y;
}

 

[Bj]

signed

I just found out that doubles are automaticlaly signed, so that means that that wasnot the problem,
:huh:
I still should run the compiler for the above code, just to see if that actually works,

 

[Bj]

:tumbleweed:

 

[computerex]

Your problem is you are not using the printf function correctly. The "%d" place holder is only for integer data type! Try this:

int sum (int x, int y)
{
    return x + y;
}

int main()
{
    /*Lets add 5 and 3 */
    int answer = sum(5,3);
    /*lets now print it to the screen */
    printf("%d + %d = %d", 5, 3, answer);
    return 0;
}

BTW, this is the add-on development forum...Shouldn't this be moved to off-topic ?

 

[Bj]

Well that should work for ints, but what about decimals?
double is used for decimals, so what if we had the sum of like
35.2345
and
67.23456

I looked it up in my book, isn't it supposed to be( %i )correct?

so just moding your code;

double sum (double x, double y)
{
    return x + y;
}

int main()
{
    int answer = sum(4.456,43.4354);
    printf("4.456 + 43.4354 = %i", answer);
    return 0;
}

oh, and yes it should be in addon development forum because I got my compiler to work with orbiter, except, I actually want to do something to it!

like for example (starting small)

using the sample-sdk it gave a starter mfd, on this mfd how do I go about printing HI!

(again starting small)
:lol:

 

[computerex]

For decimals, you use floating point variables. You can use doubles as well, but use the %f place holder. I don't do much c programming, so I haven't used printf much, but I believe %i is another place holder for int type. Try this:

double sum (double x, double y)
{
    return x + y;
}

int main()
{
    double answer = sum(4.456,43.4354);
    printf("4.456 + 43.4354 = %.4f", answer);
    return 0;
}

Orbiter is programmed in C++, not c. I have never used the printf function in coding for Orbiter, and you most likely won't be either. You use GDI to print stuff to the screen in Orbiter, not c functions that print to the STD.
I suggest that instead of learning C, you get a book on C++ and learn that instead, otherwise it can be confusing later to move from a procedural language to an object oriented language.

 

[Bj]

For decimals, you use floating point variables. You can use doubles as well, but use the %f place holder. I don't do much c programming, so I haven't used printf much, but I believe %i is another place holder for int type. Try this:

double sum (double x, double y)
{
    return x + y;
}

int main()
{
    double answer = sum(4.456,43.4354);
    printf("4.456 + 43.4354 = %.4f", answer);
    return 0;
}

Orbiter is programmed in C++, not c. I have never used the printf function in coding for Orbiter, and you most likely won't be either. You use GDI to print stuff to the screen in Orbiter, not c functions that print to the STD.
I suggest that instead of learning C, you get a book on C++ and learn that instead, otherwise it can be confusing later to move from a procedural language to an object oriented language.

you said %.4f dont you mean, %f ?

oh, and thanks for the advice on c++, I will try to buy a book from walmart or something.

 

[computerex]

%.4f will print 4 places after the decimal point. With %f you get a lot of 0s at the end of the digit.