Author |
Message |
Cancer Sol
|
Posted: Sat Mar 09, 2013 4:39 pm Post subject: Can I assign a variable with the value 0++ or something similar to that? |
|
|
Can I assign a variable with the value 0++ or something similar to that? I'm making a question from an ebook's practice question, which I need to show the first 20 squared numbers (not 20 outputs obviously though).
Here's what I tried to do:
c++: |
#include <iostream>
using namespace std;
int main ()
{
int s = 0++;
for ( int i = 0; i <= 20; i++ )
{
cout << i * s << endl;
}
}
|
|
|
|
|
|
|
Sponsor Sponsor
|
|
|
nullptr
|
Posted: Sat Mar 09, 2013 5:47 pm Post subject: Re: Can I assign a variable with the value 0++ or something similar to that? |
|
|
What exactly do you want the variable s to hold? Remember - it has to be an integer like 1 or 17. |
|
|
|
|
|
DemonWasp
|
Posted: Sat Mar 09, 2013 6:28 pm Post subject: RE:Can I assign a variable with the value 0++ or something similar to that? |
|
|
You cannot increment (++) the constant value 0, because it is constant. You could say:
Which would make s = 1.
You cannot make a simple variable that will increment every time you access it. Technically you could use macros or operator overloads or one of dozens of other tricks C++ has, but I really can't recommend it.
If you want the first 20 square numbers, though, why not just square i? |
|
|
|
|
|
Cancer Sol
|
Posted: Sat Mar 09, 2013 8:45 pm Post subject: Re: RE:Can I assign a variable with the value 0++ or something similar to that? |
|
|
DemonWasp @ 3/9/2013, 6:28 pm wrote: You cannot increment (++) the constant value 0, because it is constant. You could say:
Which would make s = 1.
You cannot make a simple variable that will increment every time you access it. Technically you could use macros or operator overloads or one of dozens of other tricks C++ has, but I really can't recommend it.
If you want the first 20 square numbers, though, why not just square i?
Ugh.. I'm so stupid LOL. It's because I saw someone else's program on some other site that was basically the same thing, but that other person did var * var instead of var squared.
How do I do i++ squared then? What's the code for it? In turing, I know it's ** , but I tried it for C++ and it didn't work :/ |
|
|
|
|
|
Insectoid
|
Posted: Sat Mar 09, 2013 8:47 pm Post subject: RE:Can I assign a variable with the value 0++ or something similar to that? |
|
|
How do you square a number on paper? |
|
|
|
|
|
Cancer Sol
|
Posted: Sat Mar 09, 2013 8:48 pm Post subject: Re: RE:Can I assign a variable with the value 0++ or something similar to that? |
|
|
Insectoid @ 3/9/2013, 8:47 pm wrote: How do you square a number on paper?
Well... I a small 2 I guess? But how do I input that on a computer? Sorry, I'm stupid
@nullptr I was trying to have var s' value just like var i, increasing by a value of 1 each time the loop loops again. |
|
|
|
|
|
Insectoid
|
Posted: Sat Mar 09, 2013 8:50 pm Post subject: RE:Can I assign a variable with the value 0++ or something similar to that? |
|
|
When you square a number, what are you actually doing to it? What is the definition of squaring? |
|
|
|
|
|
Cancer Sol
|
Posted: Sat Mar 09, 2013 9:02 pm Post subject: Re: RE:Can I assign a variable with the value 0++ or something similar to that? |
|
|
Insectoid @ 3/9/2013, 8:50 pm wrote: When you square a number, what are you actually doing to it? What is the definition of squaring?
Holy crap. I'm sooo stupid.
Well.. squaring a number is multiplying it by itself right? Is there an faster way to have a number to the power of (let's say) 40? I wouldn't want to have to multiply i 40 times |
|
|
|
|
|
Sponsor Sponsor
|
|
|
Insectoid
|
Posted: Sat Mar 09, 2013 9:11 pm Post subject: RE:Can I assign a variable with the value 0++ or something similar to that? |
|
|
Yes, but I wanted you to understand that point first . The ** operator will do any power for you. 5**2 is 5 squared. 5**10 is 5 to the power of 10. |
|
|
|
|
|
DemonWasp
|
|
|
|
|
Cancer Sol
|
Posted: Sun Mar 10, 2013 5:24 pm Post subject: Re: RE:Can I assign a variable with the value 0++ or something similar to that? |
|
|
DemonWasp @ 3/9/2013, 11:20 pm wrote: There's a function, pow, that will perform exponentiation (which is handled by the ** operator in Turing and the ^ in some languages--but NOT C or C++). Good documentation can be found here: http://en.cppreference.com/w/cpp/numeric/math/pow .
This is overkill for squaring a number. Just square it and be done.
If you want to get into fast ways to do higher powers than repeated multiplication, see: http://en.wikipedia.org/wiki/Exponentiation#Efficient_computation_of_integer_powers .
I still don't get it :/
Oh well. Thanks for all the help guys |
|
|
|
|
|
Insectoid
|
Posted: Sun Mar 10, 2013 5:32 pm Post subject: RE:Can I assign a variable with the value 0++ or something similar to that? |
|
|
Pow is a function that takes 2 arguments and returns a number (the return type depends on the arguments you pass it). The first argument is the number you want to raise to a power. The second argument is the power you want to raise it to. So, pow(5,2) is 5 squared. This function lives in math.h, so you're going to have to #include <cmath> to use it. |
|
|
|
|
|
Cancer Sol
|
Posted: Sun Mar 10, 2013 8:38 pm Post subject: Re: Can I assign a variable with the value 0++ or something similar to that? |
|
|
Thanks a lot! |
|
|
|
|
|
|