Calculate the Surface Area of a Cylinder in C

Introduction

In this lab, you will learn how to calculate the surface area of a cylinder using C programming. The lab covers the steps to read the radius and height of the cylinder from the user, and then compute the surface area using the formula 2PIr*(r+h). The program will then print the calculated surface area.

The lab provides a complete step-by-step guide, including the necessary C code, to help you understand the process of computing the surface area of a cylinder. By the end of this lab, you will have a solid understanding of how to perform geometry calculations using C programming.

Skills Graph

Read Radius and Height

In this step, you will learn how to read the radius and height of a cylinder using C programming. We'll create a simple program that prompts the user to input these values.

First, let's create a new C file in the project directory:

cd ~/project
nano cylinder_surface_area.c

Now, add the following code to the file:

#include <stdio.h>

int main() {
    float radius, height;

    // Prompt user to enter radius
    printf("Enter the radius of the cylinder: ");
    scanf("%f", &radius);

    // Prompt user to enter height
    printf("Enter the height of the cylinder: ");
    scanf("%f", &height);

    // Print the entered values
    printf("Radius: %.2f\n", radius);
    printf("Height: %.2f\n", height);

    return 0;
}

Let's break down the code:

• We use printf() to display prompts for radius and height
• scanf() is used to read float values for radius and height
• %.2f formats the output to display two decimal places

Compile and run the program:

gcc cylinder_surface_area.c -o cylinder_surface_area
./cylinder_surface_area

Example output:

Enter the radius of the cylinder: 5
Enter the height of the cylinder: 10
Radius: 5.00
Height: 10.00

Compute Surface Area = 2PIr*(r+h)

In this step, you will modify the previous program to calculate the surface area of a cylinder using the formula: Surface Area = 2PIr*(r+h).

Open the existing file and update the code:

cd ~/project
nano cylinder_surface_area.c

Replace the previous code with the following:

#include <stdio.h>
#define PI 3.14159

int main() {
    float radius, height, surface_area;

    // Prompt user to enter radius
    printf("Enter the radius of the cylinder: ");
    scanf("%f", &radius);

    // Prompt user to enter height
    printf("Enter the height of the cylinder: ");
    scanf("%f", &height);

    // Calculate surface area
    surface_area = 2 * PI * radius * (radius + height);

    // Print the results
    printf("Radius: %.2f\n", radius);
    printf("Height: %.2f\n", height);
    printf("Surface Area: %.2f\n", surface_area);

    return 0;
}

Let's break down the changes:

• Added #define PI 3.14159 to define a constant for π
• Created a surface_area variable to store the calculated result
• Used the formula: Surface Area = 2PIr*(r+h)
• Added a print statement to display the calculated surface area

Compile and run the program:

gcc cylinder_surface_area.c -o cylinder_surface_area
./cylinder_surface_area

Example output:

Enter the radius of the cylinder: 5
Enter the height of the cylinder: 10
Radius: 5.00
Height: 10.00
Surface Area: 628.32

Print the Surface Area

In this final step, you will enhance the program to provide a more user-friendly output of the cylinder's surface area.

Open the existing file and make final modifications:

cd ~/project
nano cylinder_surface_area.c

Update the code with formatted output:

#include <stdio.h>
#define PI 3.14159

int main() {
    float radius, height, surface_area;

    // Prompt user to enter radius
    printf("Cylinder Surface Area Calculator\n");
    printf("--------------------------------\n");
    printf("Enter the radius of the cylinder: ");
    scanf("%f", &radius);

    // Prompt user to enter height
    printf("Enter the height of the cylinder: ");
    scanf("%f", &height);

    // Calculate surface area
    surface_area = 2 * PI * radius * (radius + height);

    // Print formatted results
    printf("\nCalculation Results:\n");
    printf("--------------------------------\n");
    printf("Radius:        %.2f units\n", radius);
    printf("Height:        %.2f units\n", height);
    printf("Surface Area:  %.2f square units\n", surface_area);

    return 0;
}

Compile and run the program:

gcc cylinder_surface_area.c -o cylinder_surface_area
./cylinder_surface_area

Example output:

Cylinder Surface Area Calculator
--------------------------------
Enter the radius of the cylinder: 5
Enter the height of the cylinder: 10

Calculation Results:
--------------------------------
Radius:        5.00 units
Height:        10.00 units
Surface Area:  628.32 square units

Key improvements:

• Added a title for the calculator
• Included separators for better readability
• Added units to the output
• Formatted the results with clear labels

Summary

In this lab, you learned how to read the radius and height of a cylinder using C programming, and then calculate the surface area of the cylinder using the formula: Surface Area = 2PIr*(r+h). The program prompts the user to enter the radius and height, and then calculates and displays the surface area.

The key steps covered in this lab are: 1) reading the radius and height from the user, and 2) computing the surface area using the provided formula.