111
Can you please help me and explain how to create a program, which would find area of triangle and its perimeter?
Re: 111
On Saturday, 20 February 2016 at 00:01:47 UTC, cym13 wrote: On Friday, 19 February 2016 at 23:56:29 UTC, Lisa wrote: Can you please help me and explain how to create a program, which would find area of triangle and its perimeter? What do you need help for exactly? What have you tried? What do you struggle with? With everything, actually i need full explanation and listing of programm from its beginning
Re: 111
On Saturday, 20 February 2016 at 00:15:16 UTC, Chris Wright wrote: On Sat, 20 Feb 2016 00:04:04 +, Lisa wrote: On Saturday, 20 February 2016 at 00:01:47 UTC, cym13 wrote: On Friday, 19 February 2016 at 23:56:29 UTC, Lisa wrote: Can you please help me and explain how to create a program, which would find area of triangle and its perimeter? What do you need help for exactly? What have you tried? What do you struggle with? With everything, actually i need full explanation and listing of programm from its beginning Is this a homework problem that was assigned to you? Yes, exectly. It's new for me, and i don't even know how should I start.
Re: 111
On Saturday, 20 February 2016 at 01:48:35 UTC, Ali Çehreli wrote: On 02/19/2016 03:56 PM, Lisa wrote: Can you please help me and explain how to create a program, which would find area of triangle and its perimeter? It's great to have student questions on this forum. If you don't mind telling us, which teacher and school teaches or uses D? The only one that I know of is Professor Chuck Allison at Utah Valley University. Assuming that you are given the lengths of the three sides, you can calculate the area with Heron's formula. I had used that method in this otherwise unrelated chapter: http://ddili.org/ders/d.en/invariant.html Ali Thank you :) I'm actually from Ukraine)
Re: 111
On Friday, 19 February 2016 at 23:56:29 UTC, Lisa wrote: Can you please help me and explain how to create a program, which would find area of triangle and its perimeter? And for everybody - I know how to find area and perimetr, but i don't know how to write it on programming language) Can i use "scanf" in D language?
Re: 111
On Saturday, 20 February 2016 at 01:48:35 UTC, Ali Çehreli wrote:
On 02/19/2016 03:56 PM, Lisa wrote:
Can you please help me and explain how to create a program,
which would
find area of triangle and its perimeter?
It's great to have student questions on this forum. If you
don't mind telling us, which teacher and school teaches or uses
D? The only one that I know of is Professor Chuck Allison at
Utah Valley University.
Assuming that you are given the lengths of the three sides, you
can calculate the area with Heron's formula. I had used that
method in this otherwise unrelated chapter:
http://ddili.org/ders/d.en/invariant.html
Ali
import std.stdio;
import std.math;
int main()
{
double a, b, c, p;
writef("Enter a: ");
scanf("%d", &a);
writef("Enter b: ");
scanf("%d", &b);
writef("Enter c: ");
scanf("%d", &c);
p = a + b + c;
writeln("P=", p);
return 0;
}
I try to do just perimetr, but it doesn't work :(
Re: 111
On Saturday, 20 February 2016 at 03:43:17 UTC, Ali Çehreli wrote:
On 02/19/2016 07:37 PM, Lisa wrote:
> import std.stdio;
> import std.math;
>
> int main()
> {
> double a, b, c, p;
>
> writef("Enter a: ");
> scanf("%d", &a);
scanf is not a safe function. It trusts the format string and
assumes that 'a' really is what the programmer told it. (For
example, although 'a' is not an 'int, %d means 'int' and scanf
treats it as such.)
The correct format identifier for double is %lf. You need to
replace all three of with %lf.
However, you are not writing idiomatic D code. I recommend
dropping C functions altogether an taking advantage of readf():
http://ddili.org/ders/d.en/input.html
Ali
module main;
import std.stdio;
import std.math;
int main() {
int A, B, C;
writef("A = ");
readf("%lf", %A);
writef("B = ");
readf("%lf", %B);
writef("C1= ");
readf("%lf", %C);
writefl("P = (%lf)", A + B + C);
return 0;
}
It whatever doesn't work
Re: 111
On Saturday, 20 February 2016 at 12:59:58 UTC, Ivan Kazmenko
wrote:
On Saturday, 20 February 2016 at 04:15:50 UTC, Lisa wrote:
module main;
import std.stdio;
import std.math;
int main() {
int A, B, C;
writef("A = ");
readf("%lf", %A);
writef("B = ");
readf("%lf", %B);
writef("C1= ");
readf("%lf", %C);
writefl("P = (%lf)", A + B + C);
return 0;
}
It whatever doesn't work
The line "int A, B, C;" should be "double A, B, C;" if you want
to be able to operate non-integer lengths as well.
The lines like "readf("%lf", %A);" should be "readf(" %s",
&A);".
Please read the reasoning again carefully in Ali's book:
http://ddili.org/ders/d.en/input.html. The " %s" can be " %f"
but not " %lf" (that would be the correct string for C's printf
but not for D's readf), and the leading space is important.
On the output line, you perhaps meant "writefln" instead of
"writefl". Again, "%lf" should be changed into "%f" or "%s".
import std.stdio;
import std.math;
void main() {
writef("Enter side A: ");
double A;
readf("%s", &A);
writef("Enter side B: ");
double B;
readf("%s", &B);
writef("Enter side C: ");
double C;
readf("%s", &C);
writefln("Perimetr is", A + B + C, " centimetrs.");
return 0;
}
Is there smth wrong again?
Re: 111
On Sunday, 21 February 2016 at 14:03:56 UTC, Ivan Kazmenko wrote:
On Sunday, 21 February 2016 at 12:35:31 UTC, Lisa wrote:
...
Is there smth wrong again?
Yes.
As a programmer, most of the time, you will have to try your
programs by yourself before you consider them correct.
Now, run a compiler, and it complains:
-
main.d(20): Error: cannot return non-void from void function
-
Line 20 of your program is "return 0;", and the void function
in question is "void main() {...}". So, you have to fix either
of that: make main return int instead of void, or remove the
return line.
After that, the program will finally compile. But that's not
the end, you have to try running it.
"Enter side A:"
shall we say,
"1"
and then it writes
"Enter side B:"
and fails:
-
std.conv.ConvException@c:\Tools\dmd\windows\bin\..\..\src\phobos\std\conv.d(2729):
no digits seen
0x0040666A in ...
-
That's a whole lot of unfriendly error text on the screen, but
the human-readable part is "no digits seen" when reading
variable B.
Now, read the chapter of Ali's book again very carefully, or
one of the posts here. You may then notice that the space
inside the quotes is important, and also learn why.
The bottom line: the task of writing a program is not finished
until you can compile it, run it, give it at least a few
example inputs, and it prints the right output for all these
inputs.
Ivan Kazmenko.
Thank you so much! :)
Thanks everyone!) You're really cool)
