UNIVERSITY OF WEST ATTICA
SCHOOL OF ENGINEERING
DEPARTMENT OF COMPUTER ENGINEERING AND INFORMATICS

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Computer Programming

Subprograms

Vasileios Evangelos Athanasiou
Student ID: 19390005

GitHub · LinkedIn

Supervisor: Georgios Meletiou, Laboratory Teaching Staff

UNIWA Profile

Athens, December 2021

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Project Overview

This project focuses on the implementation and documentation of independent subprograms (functions) in C to solve mathematical and logical problems using Menu options for users to choose. It specifically covers the calculation of trigonometric values using Taylor series and the recursive solution to the Towers of Hanoi game.

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Table of Contents

Section	Folder / File	Description
1	assign/	Assignment material
1.1	assign/project5.png	Assignment description / problem statement (English)
1.2	assign/εργασία5.png	Assignment description / problem statement (Greek)
2	docs/	Theoretical documentation
2.1	docs/Subprograms.pdf	Functions and subprograms in C (English)
2.2	docs/Υποπρογράμματα.pdf	Functions and subprograms in C (Greek)
3	src/	Source code implementations
3.1	src/Hanoi.c	Tower of Hanoi example using recursive function
3.2	src/Menu.c	Menu-driven program demonstrating modular functions
3.3	src/SinCosTaylor.c	Computing sine and cosine using Taylor series via functions
4	README.md	Repository overview and instructions

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1. SinCosTaylor.c

This program calculates the sine and cosine of an angle (in degrees) provided by the user.
It compares results from the standard math.h library with calculations from the infinite Taylor series.

Key Features

• Input Handling: Reads an angle $\Omega$ in degrees and converts it to radians ($w$).

• Trigonometric Calculations:

  • Library Functions: sin(w) and cos(w) from math.h.

  • Taylor Series: Implements infinite series for sine and cosine:

    $$ \sin(x) = x - \frac{x^3}{3!} + \frac{x^5}{5!} - \frac{x^7}{7!} + \dots $$

• Precision Check: Compares library and Taylor results using a minimal difference threshold (e.g., $0.0000009$).

File Structure & Libraries

• stdio.h – Standard I/O (printf, scanf)
• math.h – Trigonometric functions and absolute value (fabs)
• #define pi 3.14159 – Constant for degree-to-radian conversion

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2. Hanoi.c

This program implements the Towers of Hanoi logic puzzle using recursion.

Key Features

• Disk Input: Prompts the user for the number of disks.

• Move Calculation: Computes the minimum moves required:

  $$ 2^n - 1 $$

• Recursive Solution: Implements Move_Disks to print the step-by-step movement of disks between posts A, B, and C.

Core Functions

Function	Purpose
Read_num_Disks()	Reads the number of disks from the user
Num_Min_Moves(int n)	Computes the minimum move count for n disks
Move_Disks(int n, char A, char B, char C)	Recursively prints the movement path of disks

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3. Menu.c

The program implements a loop that repeatedly displays a menu until the user chooses to exit. It tracks the total number of valid operations performed during the session and prints this sum upon exiting.

The program is modular and uses independent subroutines for specific tasks:

Input and UI Functions

• Title(): Displays the program title and headers.
• Read_A() and Read_B(): Prompts the user to enter two integers, (A) and (B).
• Exit(): Handles termination of the menu loop and returns a count for the exit operation.

Mathematical Operations

• Power ((A^B))

  • Power(int, int): Calculates (A^B).
  • Check_Power() and Check_Valid_Power(): Validate and display results.

• Factorial ((A!) and (B!))

  • Factorial(int): Computes factorial.
  • Check_Factorial_A(), Check_Factorial_B(), and Check_Factorial(): Validate inputs (e.g., negative numbers) and display results.

• Combinations ((A) per (B))

  • Combinations(int, int): Calculates $$ \frac{A!}{B!(A-B)!} $$

  • Validates that (A > B) and both numbers are non-negative.

Menu Options

When running, the user is presented with:

1. Calculation of (A^B)
2. Calculation of (A!) and (B!)
3. Calculation of the number of combinations (A) per (B)
4. Exit

Implementation Details

• Libraries: stdio.h for input/output, math.h for mathematical functions.
• Validation: Ensures errors are caught (e.g., negative factorials or invalid combinations) and displays "Error" messages.
• Operation Counter: Tracks cumulative successful executions using sum = m_P + m_F + m_C + m_E, printed when the user exits.

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Installation & Setup Guide

This repository contains introductory laboratory material for the
Computer Programming course at the University of West Attica (UNIWA).

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Prerequisites

Required Software

• C Compiler

  • Recommended:
    • GCC (Linux / macOS / Windows via MinGW or WSL)

• Text Editor or IDE

  • Visual Studio Code (Recommended)
  • Code::Blocks
  • Dev-C++
  • CLion
  • Any plain text editor

Supported Operating Systems

• Windows
• Linux (Recommended)
• macOS

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Installation

1. Clone the Repository

Clone the repository to your local machine:

git clone https://github.com/Computer-Programming-aka-Uniwa/Functions.git

Alternative (Without Git)

• Open the repository URL in your browser
• Click Code → Download ZIP
• Extract the ZIP file to a local directory

Compiling & Running the Programs

2. Navigate to Source Directory

cd Functions/src

3. Compile the Programs

gcc Hanoi.c -o Hanoi
gcc SinCosTaylor.c -o SinCosTaylor -lm
gcc Menu.c -o Menu -lm

-lm is required to link the math library

4. Run the Programs

Linux / macOS

./Hanoi
./Menu
./SinCosTaylor

Windows

Hanoi.exe
Menu.exe
SinCosTaylor.exe

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Open the Documentation

1. Navigate to the docs/ directory
2. Open the report corresponding to your preferred language:
   • English: Subprograms.pdf
   • Greek: Υποπρογράμματα.pdf