C Programming Introduction and Features .pptx

Introduction to C programming

1. Presented by M.Sri Soundharyaa Asst.Prof Department of CS with Cyber Security SRCAS

2. What is C? C is a general-purpose programming language created by Dennis Ritchie at the Bell Laboratories in 1972. It is a very popular language, despite being old. The main reason for its popularity is because it is a fundamental language in the field of computer science. C is strongly associated with UNIX, as it was developed to write the UNIX operating system.

3. The Problem-solving Aspect-Top-down Design Top-down design in C is a problem-solving approach where a complex problem is broken down into smaller, more manageable sub-problems , and then those sub-problems are further divided until they can be easily solved.  This hierarchical approach helps in organizing the code, making it more modular, readable, and easier to debug .  1. Problem Identification: The process begins by clearly defining the problem and its inputs and outputs. 

4. 2. Decomposition: The problem is then broken down into a hierarchy of sub-problems. This involves identifying the major tasks the program needs to perform and then dividing those tasks into smaller sub-tasks.  3. Function Implementation: Each sub-problem is implemented as a separate function in the C code. This promotes modularity and reusability.  4. Integration: The main function orchestrates the execution of these sub-functions, calling them in the appropriate order.  

5. 5. Testing and Debugging: The program is then tested and debugged to ensure that each sub-problem is solved correctly and that the overall program functions as expected. Example: Imagine building a house. In a top-down approach, you wouldn't start by laying the foundation and then randomly adding walls and windows.  Identify the overall problem:   Break it down into major sub-problems Further decompose each sub-problem Implement each sub-problem (function) in C buildFoundation () installPlumbing () finishInterior ()

6. Advantages of Top-Down Design in C Modularity: Breaking down the problem into smaller, independent functions makes the code more organized and easier to understand. Reusability: Functions can be reused in other parts of the program or in other projects. Testability: Each function can be tested independently, making it easier to identify and fix bugs. Maintainability: Changes in one part of the code are less likely to affect other parts of the code. 

7. Implementation of Algorithms Algorithm Refers to the logic of a problem and a step-by-step description of how to arrive at the solution of a given problem. In order to qualify as an algorithm, a sequence of instruct must have following characteristics:  Each and every instruction should be precise and unambiguous  Each instruction should be such that it can be performed in a finite time

8. Algorithms typically follow a logical structure: Input:   The algorithm receives input data. Processing:  The algorithm performs a series of operations on the input data. Output:   The algorithm produces the desired output. Algorithms are essential for solving complex computational problems efficiently and effectively. They provide a systematic approach to: Solving problems :  Algorithms break down problems into smaller, manageable steps. Optimizing solutions :  Algorithms find the best or near-optimal solutions to problems. Automating tasks :  Algorithms can automate repetitive or complex tasks, saving time and effort.

9. One or more instructions should not be repeated infinitely, This ensures that the algorithm will ultimately terminate Example : Algorithm for Simple Interest Step 1 : Start Step 2 : Read p,n,r Step 3 : Calculate si = p * n * r /100 Step 4 : Print si Step 5 : Stop

10. Flowchart is a pictorial representation of an algorithm

11. C-Algorithms In programming, algorithm are the set of well defined instruction in sequence to solve a program . An algorithm should always have a clear stopping point. Write an algorithm to add two numbers entered by user. Step 1: Start Step 2: Declare variables num1, num2 and sum. Step 3: Read values num1 and num2. Step 4: Add num1 and num2 and assign the result to sum. sum = num1+num2 Step 5: Display sum Step 6: Stop

12. Flowchart to add two numbers

13. The Efficiency of Algorithms- Efficiency is measured in terms of  time  and  space . The Analysis of Algorithms -Analysis of Algorithms is a fundamental aspect of computer science that involves evaluating performance of algorithms and programs .

14. Algorithm analysis is an important part of computational complexity theory, which provides theoretical estimation for the required resources of an algorithm to solve a specific computational problem. Analysis of algorithms is the determination of the amount of time and space resources required to execute it.

15. Why Analysis of Algorithms is important? To predict the behavior of an algorithm for large inputs (Scalable Software). It is much more convenient to have simple measures for the efficiency of an algorithm than to implement the algorithm and test the efficiency every time a certain parameter in the underlying computer system changes. More importantly, by analyzing different algorithms, we can compare them to determine the best one for our purpose.

16. Fundamental Algorithms Exchanging the values of two variables , often called swapping, is a fundamental operation in programming and problem-solving.  It's commonly used in algorithms like sorting and searching.  The simplest method involves using a temporary variable to hold one value while the exchange takes place. 

17. Algorithm: Step 1: Start Step 2: Take the value of variables a and b. Step 3: Assign the value of variable a into the temp variable. Step 4: Assign the value of variable b into a variable. Step 5: Assign the value of variable temp into the b variable. Step 6: Print the value of a and b.

18. Sum of Natural Numbers Using for Loop include < stdio.h > int main() { int n, i, sum = 0; printf ("Enter a positive integer: "); scanf ("%d", &n); for (i = 1; i <= n; ++i) { sum += i; } printf ("Sum = %d", sum); return 0; ; }