C Program to Find Surface Area and Volume of a Cylinder

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Introduction

Cylinders are three-dimensional shapes with two parallel circular bases connected by a curved surface. They are commonly used in various real-world applications, such as pipes, cans, and tanks. Understanding how to calculate the surface area and volume of a cylinder is essential for many engineering, construction, and design tasks.

In this tutorial, we will learn how to calculate these properties using a C program. The surface area determines how much material is needed to cover the cylinder, while the volume measures the space it occupies.

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Formulas for Surface Area and Volume

The calculations for surface area and volume depend on two key inputs:

• Radius (r): The distance from the center to the edge of the circular base.
• Height (h): The vertical distance between the two bases.

Here are the formulas:

• Surface Area: The total surface area of a cylinder consists of:
  • The area of the two circular bases: 2 × π × r²
  • The curved surface area: 2 × π × r × h
  Combined, the formula becomes: Total Surface Area = 2 × π × r × (r + h)
• Volume: The volume is calculated as the product of the area of the base and the height:
  Volume = π × r² × h

In the program, we will use 3.14159 as the value of π for simplicity.

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C Program Code

Here is the C program to compute the surface area and volume of a cylinder:

#include <stdio.h>

#define PI 3.14159

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

    // Input radius and height of the cylinder
    printf("Enter the radius of the cylinder: ");
    scanf("%f", &radius);
    printf("Enter the height of the cylinder: ");
    scanf("%f", &height);

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

    // Display the results
    printf("Surface Area of the cylinder: %.2f\n", surface_area);
    printf("Volume of the cylinder: %.2f\n", volume);

    return 0;
}
    

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Output

Here is an example of the output when the program is executed:

Enter the radius of the cylinder: 3
Enter the height of the cylinder: 5
Surface Area of the cylinder: 150.80
Volume of the cylinder: 141.37
    

The program calculates the total surface area and volume based on the inputs provided by the user. The results are displayed with two decimal places for better readability.

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Explanation of the Program

Let’s break down the program to understand its logic and structure:

• Input: The program uses the scanf function to take two inputs from the user: the radius and height of the cylinder. These values are stored in the variables radius and height.
• Constants: The value of π is defined as a constant using the #define preprocessor directive. This makes the code cleaner and more efficient.
• Calculations:
  • The surface area is computed using the formula 2 × π × r × (r + h), and the result is stored in the variable surface_area.
  • The volume is computed using the formula π × r² × h, and the result is stored in the variable volume.
• Output: The printf statements display the calculated values of surface area and volume. The %.2f format specifier ensures that the results are shown with two decimal points.
• Return Value: The return 0; statement indicates that the program executed successfully.