Coding with Function problem

[SamT1234]

I am working on a code using a function, to calculate the area and circumference of a circle once the radius is collected from the user. The issue I am experiencing is after I get the radius from the user, The program exits before excuting the function. I entered my code so far. Any help would be appreciated.

Thank you.


#include<iostream>
#include<cmath>
using namespace std;
double circumferencecalc(double circumference,double x);
int main()
{
double radius;
double area = radius*radius*3.14159;

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

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

}

double circumferencecalc(double circumference, double x)
{
double radius;
cout << "The circumference of the circle is " << circumference << endl;

system("pause");
return circumference;
}

[keskiverto]

Your previous thread about this program is: http://www.cplusplus.com/forum/beginner/202867/

I told there that you should read something. Do it again, carefully.

[alonso12]

Hello,

Your trying to calclate the area before you input the radius.
You never call "double circumferencecalc(double circumference, double x)" from main.
Apart from that the circumference of a circle is 2 x Radius x Pi.
Main should return a value (0 or 1, success or failure).
Try these adjustments and repost (Please use code tags).

Regards

#include<iostream>
#include<cmath>
using namespace std;
double circumferencecalc(double circumference,double x);
int main()
{
double radius;
double area = radius*radius*3.14159;

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

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

}

double circumferencecalc(double circumference, double x)
{
double radius;
cout << "The circumference of the circle is " << circumference << endl;

system("pause");
return circumference;
}

[SamT1234]

All:

I really appreciate the help. I am still struggling with getting the main function to transfer into the function I added. My new code is below. Not really sure if I am close or completely off. Do we know of any examples I could look at?

#include<iostream>
using namespace std;
double calculatecircumference(double);
int main()
{
double i;
cout << "Please enter the radius of the circle: ";
cin >> i;

cout << calculatecircumference(i);


double calculatecircumference(double);
{

if (i > 0)
{
double area = 3.14159 * i*i;
double circumference = 2 * 3.14159*i;
cout << "The area of your circle is: " << area << endl;
cout << "The circumference of your circel is: " << circumference << endl;
}
else
cout << "Please enter a positive integer." << endl;

system("pause");
return 0;
}

}

[integralfx]

Please use code tags. http://www.cplusplus.com/articles/jEywvCM9/
You can edit your post, highlight your code and click the <> button on the right.

You can't define a function in a function.

#include <iostream>
using namespace std;

// give these magic numbers a name to help
// with readability
const double PI{ 3.14159 };

double calculate_circumference( double );
double calculate_area( double radius );

int main( )
{
    // use more descriptive names
    double radius;
    cout << "Please enter the radius of the circle: ";
    cin >> radius;

    cout << "circumference = " << calculate_circumference( radius ) << "\n";
    cout << "radius = " << calculate_area( radius ) << "\n";
}

// this function is made to calculate the circumference
// and return it -> no more and no less
// also please use underscores or camel case
// so that the function doesn't look like a reallylongwordlikethis
double calculate_circumference( double radius )
{
    // invalid radius so we return an invalid circumference
    // that way we can check in the calling function
    if( radius < 0.0 ) return -1.0;
    return 2 * PI * radius;
}
double calculate_area( double radius )
{
    if( radius < 0.0 ) return -1.0;
    return PI * radius * radius;
}

[SamT1234]

All:

Thank you. I am reviewing and studying this for better understanding. Again everything from everyone is appreciated.

Also thank you for the link to code tags, I didn't know how to do that either.