# 1. Introduction

Arithmetic operations are foundational in programming, serving as an excellent starting point for newcomers to grasp basic coding concepts. In this tutorial, we will learn how to write a simple C program to subtract two given numbers.

# 2. Program Overview

Our program's workflow is as follows:

1. Prompt the user to input two numbers.

2. Read and store the numbers.

3. Subtract the second number from the first.

4. Display the result.

# 3. Code Program

``````#include <stdio.h>  // Incorporate the Standard I/O library for functions related to input and output

int main() {  // This is where our program begins its execution

double num1, num2, difference;  // Declare three variables of type double: two for the user's numbers and one for the result

// Ask the user to input their numbers
printf("Enter the minuend (number to be subtracted from): ");
scanf("%lf", &num1);  // Capture and save the first number

printf("Enter the subtrahend (number to subtract): ");
scanf("%lf", &num2);  // Capture and save the second number

difference = num1 - num2;  // Perform the subtraction operation

printf("The difference between %.2lf and %.2lf is: %.2lf\n", num1, num2, difference);  // Showcase the result

return 0;  // Denotes successful execution
}

``````

### Output:

```Enter the minuend (number to be subtracted from): 20
Enter the subtrahend (number to subtract): 12
The difference between 20.00 and 12.00 is: 8.00
```

# 4. Step By Step Explanation

1. #include <stdio.h>: By adding this, we integrate the standard input/output library, essential for functions such as printf and scanf.

2. int main(): Recognized as the program's entry point, every C program springs to life from the main function.

3. double num1, num2, difference;: In this segment, we're reserving space for three variables of the double type. These will store our two numbers and the resulting difference.

4. The printf function: Primarily for showing prompts and messages to the user.

5. The scanf function: It's pivotal for reading user input. We use %lf since we're working with the double type. The ampersand (&) denotes the memory address of our variable, specifying where to store the input.

6. difference = num1 - num2;: Here, the subtraction takes place.

7. return 0;: A common convention, this indicates that the program ended without any hitches.

This basic program serves as a stepping stone, introducing fundamental concepts of C programming, especially regarding user interactions and arithmetic operations.