Calculations in cout

[Deathheart14]

I am trying to figure out how to calculate a formula in my cout line and then display the answer. Could someone help me figure this out?

[GritzAgravy]

What is the desired formula?

[Deathheart14]

The formula is:

diameter = radius + radius

I have this as the cout

cout << "The diameter of the circle is : " << diameter << endl << endl;

I just need to get the formula into the cout and I am at a loss on how to do this.

[GritzAgravy]

I need to see your code to help you.

[Deathheart14]

#include <iostream>
#include <string>

using namespace std;

float pi = 3.1415926;

void main () {

	// input variables

	float radius;

	// processing variables

	float diameter,
		circumference,
		area;

	// input section

	cout << "This program will take the radius of the circle that you enter and give you the diameter, circumference, and area of the circle." << endl << endl;

	cout << "Please enter the radius of the circle: ";
	cin >> radius;

	// processing section


	 diameter = radius + radius;

	 area = radius * radius * pi;
	
	circumference = pi * diameter ;

	// output section

	cout << "The diameter of the circle is : " << diameter << endl << endl;

	cout << "The area of the circle is : " << area  << endl << endl;

	cout << "The circumference of the circle is : " << circumference << endl;

	system ("pause");


}

[GritzAgravy]

The code compiles. What happens when you run it?

[Deathheart14]

I get it to work great this way. I just need them to do the calculations in the output statment

[GritzAgravy]

This program will take the radius of the circle that you enter and give you the
diameter, circumference, and area of the circle.

Please enter the radius of the circle: 10.5
The diameter of the circle is : 21

The area of the circle is : 346.361

The circumference of the circle is : 65.9734
Press any key to continue . . .

are you not getting this when you run it?

[Deathheart14]

I do. The program itself works correctly. The problem i am having is i need to move the formulas into the cout kind of like this :

cout << diameter = radius + radius << "The diameter of the circle is : " << diameter << endl << endl;

But that will cause errors and I do not know how to make it work with the formulas within the output statement.

[GritzAgravy]

Try
cout << diameter << " = " << radius << " + "<< radius<< ...;

[Deathheart14]

I guess I should have been more specific i need it to preform the calculation and then display the answer. I do not need to show the formula itself. Sorry for the confusion.

[Deathheart14]

I ended up figuring it out. Thank you for your time in trying to help me. It was greatly appreciated.


Here is the final code :

#include <iostream>
#include <string>

using namespace std;

float pi = 3.1415926;

void main () {

	// input variables

	float radius;

	// processing variables

	float diameter,
		circumference,
		area;

	// input section

	cout << "This program will take the radius of the circle that you enter and give you the diameter, circumference, and area of the circle." << endl << endl;

	cout << "Please enter the radius of the circle: ";
	cin >> radius;

	
	// output section

	cout << "The diameter of the circle is : " << radius + radius << endl << endl;

	cout  << "The area of the circle is : " << radius * radius * pi << endl << endl;

	cout << "The circumference of the circle is : " << pi * ( radius + radius ) << endl;

	system ("pause");


}

[GritzAgravy]

You are welcome! I am gladd you got it!