Function program won't compile

AchillesO23 (31)
Any particular reason my code isn't working? I'm trying to use a function in a function to find the volume of a cylinder. Any help would be appreciated thanks.

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  #include <iostream>

using namespace std;

float areaofcircle(float circle, int radius)
{
	//scope of the function
	float area = 0;

	area = circle * radius;
	return area;
}

float volumeofcylinder(float areaofcircle, int height)
{
	//volume of cylinder = areaofcircle * height
	float cylinder = 0;
	cylinder = areaofcircle * height;
		return cylinder;
}
int main()
{
	float radius = 2.5;
	float heightofcylinder = 5.0;

	float cylinder = volumeofcylinder(float radius, float heightofcylinder)
		cout << cylinder;
	cin.get();
	cin.get();
}


Also it said I had problems at line 26
Last edited on
SakurasouBusters (732)
float cylinder = volumeofcylinder(float radius, float heightofcylinder)

Should be :
float cylinder = volumeofcylinder(radius, heightofcylinder); // Don't forget the semi-colon (;)!
AchillesO23 (31)
Thank you I got it fixed and the answer was 12.5 but I did the calculations myself and got 98 as my answer
SakurasouBusters (732)
Thank you I got it fixed and the answer was 12.5 but I did the calculations myself and got 98 as my answer

How was 98 calculated?
AchillesO23 (31)
well the volume of a cylinder is pi*r^2*height
pi* (2.5)^2*5 gives me 98
SakurasouBusters (732)
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float volumeofcylinder(float areaofcircle, int height)
{
	//volume of cylinder = areaofcircle * height
	float cylinder = 0;
	cylinder = areaofcircle * height;
	return cylinder;
}


Should be : 
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float volumeofcylinder(float areaofcircle, int height)
{
	float cylinder = 3.14 * (areaofcircle * areaofcircle) * height;
	return cylinder;
}
Last edited on
AchillesO23 (31)
wow that makes sense now thank you so much!
RobiBue (15)
Just to make sure something important does not get forgotten, I do have a few points that need to be looked into by the OP:

1. 
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float areaofcircle(float circle, int radius)
{
	//scope of the function
	float area = 0;

	area = circle * radius;
	return area;
}


if radius receives a float value (i.e. 2.5) then it will lose precision and end as a radius of 2 because it is defined as an integer in the function.
I would change the above function anyway and remove the first parameter float circle
and fix the formula for area.

2.
The same will happen with the height of the cylinder in 

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float volumeofcylinder(float areaofcircle, int height)
{
	//volume of cylinder = areaofcircle * height
	float cylinder = 0;
	cylinder = areaofcircle * height;
		return cylinder;
}


where height is also defined as an integer.

3.
In the main() function, I would think of replacing
float cylinder = volumeofcylinder(float radius, float heightofcylinder)

with
float cylinder = volumeofcylinder( areaofcircle(radius), heightofcylinder);

With corrections made, the value printed would be in the range of 98.1748 depending on the precision of pi. (given r=2.5 and h=5.0)
AchillesO23 (31)
makes sense thank you
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