Circumference of a Circle

   Circumference and Area of a Circle

Compute the area and circumference of a circle given the radius. The input/output behavior of the program should be

Circle radius(real number)?     5.1

Area of Circle with radius 5.1 is 81.7104

Circumference is 32.0433



Before we can the program , we must consider a number of issues. Recall that the area of a circle is . C++ does not have a exponentiation operator, but this operation is easily handled by multiplying the radius is Radius, the area of the circle can be computed by the expression


Because we wish to allow  the user to input a floating-point value as the radius, Radius should be a C++ floating-point type. Since the problem statement did not specify the possible size of the radius, or the accuracy of the result, we will arbitrarily choose type float for Radius.

//Program area and circumference of circle given radius



void main()


     cout<<"circle radius(real number)?";

     float Radius;


     cout<<"Area of circle with radius"<<Radius<<"is"<<(3.1415*Radius*Radius)<<endl;

     cout<<"Circumference is"<<3.1415*2*Radius<<endl;




Circumference of a circle