Computer Science Canada Can I assign a variable with the value 0++ or something similar to that? |
| Author: | Cancer Sol [ 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:
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| Author: | nullptr [ 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. |
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| Author: | DemonWasp [ 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? |
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| Author: | Cancer Sol [ 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 :/ |
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| Author: | Insectoid [ 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? |
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| Author: | Cancer Sol [ 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. |
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| Author: | Insectoid [ 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? |
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| Author: | Cancer Sol [ 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 |
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| Author: | Insectoid [ 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. |
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| Author: | DemonWasp [ Sat Mar 09, 2013 11:20 pm ] |
| Post subject: | RE:Can I assign a variable with the value 0++ or something similar to that? |
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 . |
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| Author: | Cancer Sol [ 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  |
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| Author: | Insectoid [ 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. |
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| Author: | Cancer Sol [ 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! |
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