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C++,
Help needed! I need a Program that does this: http://screencast.com/t/BFLvrQUh5b
Apparently there is something wrong with my code but I don't know why! The behaviour is not correct.
 11 months ago
 11 months ago
C++, Help needed! I need a Program that does this: http://screencast.com/t/BFLvrQUh5b Apparently there is something wrong with my code but I don't know why! The behaviour is not correct.
 11 months ago
 11 months ago

This Question is Closed

ChristosBest ResponseYou've already chosen the best response.0
#include <iostream> using namespace std; int main() { int InitialValue,NumberOfYears,counter=9,counter2=1,counter3=1,ValueAfterAYear; cout << "Give me the initial value : "; cin >> InitialValue; cout << "Give me the number of the years of that car : "; cin >> NumberOfYears; ValueAfterAYear = InitialValueInitialValue*30/100; if (NumberOfYears <= 8) { while (counter3 <= NumberOfYears) ValueAfterAYear = ValueAfterAYearValueAfterAYear*10/100; counter3++; } if (NumberOfYears > 8) { while (counter2 <= 8) { ValueAfterAYear = ValueAfterAYearValueAfterAYear*10/100; counter2++; } while (counter < NumberOfYears) { ValueAfterAYear = ValueAfterAYearValueAfterAYear*5/100; NumberOfYears; } } if (ValueAfterAYear < 500) ValueAfterAYear = 500; cout << "The value of the car is " << ValueAfterAYear; return 0; }
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
I'll open up Visual Studio in a minute, just tell me exactly what you want to the program to do. I'm assuming you're getting a logic error since you say "The behaviour is not correct".
 11 months ago

ChristosBest ResponseYou've already chosen the best response.0
Yes right, I am getting a logic error. My code's syntax is 100% correct. I don't want you to do me the program. If it's possible just tell me where it lacks logic so that I can learn to make better
 11 months ago

ChristosBest ResponseYou've already chosen the best response.0
* * * The program has to do this: http://screencast.com/t/BFLvrQUh5b
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
Look here: while (counter3 <= NumberOfYears) ValueAfterAYear = ValueAfterAYearValueAfterAYear*10/100; counter3++; It's an infinite loop. Remember that if you don't include {} only the FIRST line is included in the loop. Wrap it in {}.
 11 months ago

ChristosBest ResponseYou've already chosen the best response.0
Oh right! Hold on lemme check!
 11 months ago

ChristosBest ResponseYou've already chosen the best response.0
Ok now runs and it gives me results. for example this: Give me the initial value : 5000 Give me the number of the years of that car : 5 The value of the car is 2068 But with the calculator it gives me 2551.5
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
Are you using an IDE, like Visual Studio, or a CLI compiler like gpp/g++? Just wondering since debugging things like this is easy with breakpoints, etc
 11 months ago

ChristosBest ResponseYou've already chosen the best response.0
hm I am using Xcode (Mac application)
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
Alright, well I haven't used that, but just for future reference learning how to use breakpoints will really help things :) Anyway: I'll check the logic of your program, sec
 11 months ago

ChristosBest ResponseYou've already chosen the best response.0
I also have Visual Studio 2010 and Visual Studio 2012 I can run the code on those programs too on Virtual Machine
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
check the answer of the equation: Initial value: 5000 years: 5 5000  5000 * 30/100 = 3500 3500  3500 * 10/100 = 3150 3150  3150 * 10/100 = 2835 2835  2835 * 10/100 = 2551.5 (2552) That accounts for 5 years Your program IS, in fact, actually getting that result consider the value of counter 3, and how many times it's looping
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
I hope that's a good hint for you
 11 months ago

ChristosBest ResponseYou've already chosen the best response.0
Really? For you it gets this result? Look here: http://screencast.com/t/3uQDOhBe This is the result from me
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
You're changing the value from 5000 to 3500 BEFORE the loop; so: First iteration: 3150 Second iteration: 2835 ###Third iteration: 2552 ### Fourth iteration: 2297
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
also, you'll notice that it proves the wrong results consistently except for the third iteration in this case
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
i'm 90% sure i know why that is, let me just check
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
Initial value: 5000 years: 5 5000  5000 * 30/100 = 3500 3500  3500 * 10/100 = 3150 3150  3150 * 10/100 = 2835 2835  2835 * 10/100 = 2551.5 (2552)
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
You're changing the value from 5000 to 3500 BEFORE the loop; so: First iteration: 3150 Second iteration: 2835 ###Third iteration: 2552 ### Fourth iteration: 2297
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
Do you see the problem?
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
You're looping through 5 times even though a) the first year (5000) is taken care of, and the second year (removing 30%) is taken care of
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
well consider how many years have already passed when the while loop starts
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
i would advise setting your counter to start at that
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
counter3=2, and while (counter3 < NumberOfYears) fixes your problem
 11 months ago

ChristosBest ResponseYou've already chosen the best response.0
Yea I did this and the first part is completely done
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
so it's all fixed? :)
 11 months ago

ChristosBest ResponseYou've already chosen the best response.0
Hey something last, Would it be possible to tell me how to make use of those "breakpoints" in Visual Studio?
 11 months ago

ChristosBest ResponseYou've already chosen the best response.0
Ok Should I open 2010 or 2012 ??
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
http://i.imgur.com/BMAdkTm.png see that red dot the arrow points to?
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
That's a breakpoint. By putting that there, it tells the program to pause execution at that point.
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
You can then press F10 to step through the program, line by line, or F5 to continue until the next breakpoint
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
the value of this is it lets you see the values stored in your variables when the program isn't finished yet
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
so you can see the use of this when it comes to debugging. For example, I figured out your problem by putting a breakpoint inside the while loop, and checking the value of valueAfterAYear every iteration.
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
So put a breakpoint next to ValueAfterAYear = ValueAfterAYearValueAfterAYear*10/100; (You can do this by clicking on the gray bar on the far left)
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
lemme know when you're put a breakpoint there :)
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
have you started the program in debug mode, and entered your values (5000, and 5) in this case?
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
http://i.imgur.com/uoHs6hZ.png look at where ive highlighted in a red box
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
do you see something similar to this?
 11 months ago

ChristosBest ResponseYou've already chosen the best response.0
yea there is the same exact box on me too
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
k put your mouse over ValueAfterAYear in the code
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
when you do that it should come up with "3500", you can do that with any variable within the scope when you're debugging
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
try it with other variables too
 11 months ago

ChristosBest ResponseYou've already chosen the best response.0
ooh I see!! very useful!!
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
you'll notice the error jump down a line
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
and ValueAfterAYear has now changed to 3150
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
you can look at it from either the box or from mouseovering it
 11 months ago

ChristosBest ResponseYou've already chosen the best response.0
I noticed the 3150 but what do you mean by an error??
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
sorry i mean arrow***
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
the arrow on the left
 11 months ago

ChristosBest ResponseYou've already chosen the best response.0
aaah yea there is one
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
ok, keep pressing F10 until you're back at where we are now
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
if you want to skip going line by line, you can just pres F5 and it will go to the next breakpoint (since were in a loop it goes back to the same breakpoint)
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
you can also set breakpoints while your code is running
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
and if you want, double click the value of ValueAfterAYear in the auto's box, you can actually change the value if you want
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
things like this are so useful when trying to fix a logic problem
 11 months ago

ChristosBest ResponseYou've already chosen the best response.0
but if I change the value will the code change too, so that it corresponds to the changed value?
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
the actual code itself doesn't change, but within the program itself, the value changes, so it executes as per your changed value
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
you don't change the value mid program much, it's just a useful thing to know in case you ever need to do that
 11 months ago

AntearaBest ResponseYou've already chosen the best response.2
think you understand breakpoints now?
 11 months ago

ChristosBest ResponseYou've already chosen the best response.0
Yea I will use them a lot with nested loops and such! You have no idea how this helps !! :)
 11 months ago
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