// P33_2.cpp This program illustrates the local and global variables and call-by-value. // This program computes the side area and the cross section area of a cylinder #include #include using namespace std; double PI = 3.14159; // This variable is defined globally, known to all functions in this program as PI double cross_area(double r); // Function prototype for function cross_area double side_area(double r, double h); // Function prototype for function Side_area int main(void) { double h, r; //variables local to the main function cout << "Enter the radius and the height of the cylinder in Cm "; cin >> r >> h; cout << endl; cout << "Before I do any computation or call any function, I want to let you know that "; cout << "you have entered r = " << r << " and h = " << h << "." << endl; cout << "I am planning to use inch, thus in the first function, I will convert r, and " << endl; cout << "in the second one I will convert h "; cout << "The cross section area of the cylinder is " << cross_area(r) << " inch-sqr endl; cout << "The side area of the cylinder is " << side_area(r,h) << " inch-sqr "; return 0; } double cross_area(double r) { //Cross secion area includes the disks at the bottom and the top r = r * 0.3937; // converting r to inch return 2*PI*pow(r,2); } double side_area(double r, double h) { double area; //variable local to Side_area function h = h * 0.3937; // converting h to inch area = 2*PI*r*h; return area; }

Exercise 3.6 Copy or cut and paste program P33_2.cpp to a new program called ex36.cpp. Compile and run the program for the following values: r = 2 Cm, h = 10 Cm The answer should be: The cross section area of the cylinder is 3.8955634 c The side area of the cylinder is 19.474819 inch-sqr Did you get the same answer? Explain the reason for such an error and fix the problem. Exercise 3.7 Modify the ex36.cpp to include a new function called total_area, that computes the total suface area of a cylinder. The total surface area is the sum of side area and cross section area. Call your new program ex37.cpp. For the above test values the total area must be: 23.370382 inch-sqr