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

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Computer Programming

Introduction to C Programming

Vasileios Evangelos Athanasiou
Student ID: 19390005

GitHub · LinkedIn

Supervisor: Georgios Meletiou, Laboratory Teaching Staff

UNIWA Profile

Athens, October 2021

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Project Overview

This report covers the fundamental concepts of the C programming language, including:

• The definition of a computer program
• The software development lifecycle
• Categories of programming errors

In addition, it presents a practical analysis of a C program designed to perform basic arithmetic operations on integers, highlighting common mistakes and their corrections.

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Table of Contents

Section	Folder / File	Description
1	assign/	Assignment material
1.1	assign/project1.png	Assignment description / problem statement (English)
1.2	assign/εργασία1.png	Assignment description / problem statement (Greek)
2	docs/	Theoretical documentation
2.1	docs/Introduction.pdf	Introductory theory and concepts (English)
2.2	docs/Εισαγωγή.pdf	Introductory theory and concepts (Greek)
3	src/	Source code implementations
3.1	src/C1aCorrect.c	Correct implementation of the exercise
3.2	src/C1aWrong.c	Incorrect implementation (for comparison / analysis)
4	README.md	Repository overview and instructions

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1. Theory Fundamentals

1.1 What Is a Program?

A program is defined as a sequence of commands provided by a user to solve a specific problem. These commands instruct the computer on how to process data and produce the desired output.

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1.2 Steps of C Program Development

The report outlines the following seven key stages involved in developing and executing a C program:

1. Editing
   Writing the source code using a C programming environment.

2. Saving
   Storing the source code in a file with the .c extension.

3. Compilation
   Using a compiler to detect and report syntax errors in the source code.

4. Machine Language Conversion
   Translating the corrected source code into an object file (.obj) that the processor can understand.

5. Linking
   Connecting the object file with required libraries (e.g., stdio.h) to produce an executable file (.exe).

6. Executable Generation
   Finalizing the executable file so it can be run by the operating system.

7. Running
   Executing the program to perform its intended operations and produce output.

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1.3 Categories of Program Errors

Error Type	Description	Example
Syntax Error	Violations of the language’s grammatical rules	Missing semicolon or quotation mark
Logical Error	Errors in logic that the compiler cannot detect	Using subtraction instead of addition
Runtime Error	Errors that occur during execution and stop the program	Division by zero

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2. Practical Source Code Analysis

The paper analyzes two versions of a C program:

• C1aWrong.c – Contains multiple errors
• C1aCorrect.c – Corrected version of the program

2.1 Common Syntax Errors Identified

• Missing Quotes
  Failure to close a string literal in a printf() statement.

• Case Sensitivity
  Attempting to use a lowercase variable (c) when it was declared as uppercase (C).

• Character Encoding Issues
  Using a Greek character "Ε" instead of the Latin "E" in a variable name.

• Typographical Errors
  Misspelling printf as prantf, which is detected during the linking stage.

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3. Execution Examples and Observations

The program was tested using various integer inputs to demonstrate how C handles arithmetic operations.

3.1 Integer Division

When performing the operation:

5/10

The program returns:

0

This occurs because both operands are declared as int. As a result, the decimal portion of the division is truncated, not rounded.

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3.2 Integer Overflow

Using very large values (e.g., 54,645,234,234) produces incorrect negative results.
This behavior is caused by integer overflow, where the value exceeds the maximum range supported by the standard int data type.

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Installation & Setup Guide

This repository contains introductory material and example source code for C programming, developed for the Computer Programming course at the University of West Attica (UNIWA).

The project includes theoretical documentation and simple C source files intended for compilation and execution on a local machine.

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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/Intro.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 Intro/src

3. Compile the Correct Program

Using GCC:

gcc C1aCorrect.c -o C1aCorrect

4. Run the Program

Linux / macOS:

./C1aCorrect

Windows:

C1aCorrect.exe

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Open the Documentation

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