How to Write a C Program to Print the Arithmetic Series -2, -4, -6, -8, -10, -12...n

Mastering the art of writing efficient and readable C programs opens up a plethora of possibilities in the world of software development. One common task is to write a program that prints a specific arithmetic series according to user-defined limits. In this article, we will delve into a simple yet effective solution to print the series -2, -4, -6, -8, -10, -12...n in C.

Understanding the Series

The series in question is an arithmetic progression where the first term is -2, and each subsequent term decreases by 2. This is analogous to a sequence where the first term (a) is -2 and the common difference (d) is also -2.

Steps to Write the C Program

Include the Necessary Libraries: Start by including the stdio.h library that provides essential input and output functions. Declare Variables: Declare an integer variable to hold the user's input for the limit of the series. User Input: Prompt the user to enter the value of n, which determines the end of the series. Loop to Print the Series: Use a for loop to iterate from -2 down to n, decrementing by 2 until the condition is met. Output Formatting: Print each term in the series with proper formatting for clear readability.

Sample Code and Explanation

h3Sample Code/h3#include stdio.hint main() {   int n;   /* Prompt the user for input */   printf(Enter the limit n: );   scanf(%d, n);   /* Print the series */   printf(The series is:
);   for (int i  -2; i  n; i - 2) {      printf(%d , i);   }   printf(
);   return 0;}

Explanation:

Include Standard I/O Library: We include the stdio.h header file to use input and output functions. Declare Variables: We declare an integer variable n to store the user's input. User Input: We prompt the user to enter the value of n, which determines the limit of the series. Loop to Print the Series: The loop starts from -2 and decrements by 2 in each iteration until it reaches or goes below n. The condition i n ensures that we stop printing when the current term is less than or equal to n. Output Formatting: A newline is printed after the series for better readability.

Example Output

If the user inputs -12, the output will be:

The series is:
-2 -4 -6 -8 -10 -12

This program can be compiled and run using any C compiler. Adjust the input for different ranges as needed!

Case Studies: Definite vs. Indefinite Loops

Let's explore two cases that might arise when implementing the loop condition:

Case i: Definite Upto a Particular Number

Here the condition is defined until a particular value, say -100.

int n -2; while (n -100) /this condition goes on until n becomes -100 when n becomes -102 the condition becomes false and gets out of the loop/{ printf(%d , n); n - 2;}

Explanation: The loop runs until n reaches the specified limit. The loop condition ensures that the loop stops when n becomes less than -100.

Case ii: Indefinite Loop

In this scenario, the condition always holds true, which effectively creates an infinite loop. Since n is negative, it continuously decreases, making the condition always true, until the loop is explicitly exited.

Code:

while (n ! 0 || n ! any positive number like 123)/* since n is negative it continuously goes on left hand side of number line and never reaches right hand side numbers. Some compilers may show error for indefinite loop some dont. */

Explanation: An indefinite loop can lead to issues, and it is generally best to avoid it unless it is intended for specific use cases. Be cautious when handling such loops to prevent potential infinite execution.

Feel free to experiment with these concepts and share your thoughts in the comments below!