Linguagem C - Aula 1.1 - Aprenda a usar o DEV C++ (2022)

Introduction to Programming Logic in C

Course Overview

• The course aims to teach programming logic using the C language, while also touching on other languages like Visual and pseudocode.

• Instructor Pietro introduces himself as a master's graduate in Computer Science with experience in backend development and teaching since 2016.

Instructor's Background

• Pietro has worked as a Junior Developer and Analyst, primarily focused on telecommunications and health systems.

• He emphasizes the common struggles beginners face when learning programming, highlighting the importance of overcoming these challenges.

Learning Approach

• Active participation is crucial; students are encouraged to solve exercises and execute source codes rather than just watching videos.

• The first lesson will cover the history of C language briefly, focusing on its characteristics without delving too deeply into historical context.

Understanding the C Language

Historical Context

• The instructor mentions that C was created by Dennis Ritchie at Bell Labs in 1972 to simplify programming compared to assembly language.

• The goal was to create a high-level language that could unify various low-level languages for easier coding across different processors.

Characteristics of C Language

• Despite being considered a low-level language by some, it is classified as high-level due to its ability to work closely with hardware while maintaining simplicity.

• C remains relevant today for developing operating systems (like Windows and Linux), desktop applications, embedded systems, and IoT devices.

Relevance of C Today

Current Applications

• The instructor discusses how C is commonly used in standalone applications and embedded systems such as smart TVs or automotive computers.

Performance Attributes

Understanding the C Programming Language

Performance and Characteristics of C

• C is an interpreted language with a software layer between source code and execution, which can lead to lower performance compared to compiled languages like C.

• The course focuses on teaching programming logic rather than performance analysis; however, for high-performance systems, C is often a preferred choice due to its proximity to hardware resources.

• C allows for detailed memory manipulation and specific input/output device handling, offering powerful capabilities that may not be available in other languages.

• While the syntax of C can be complex, mastering it provides a strong foundation for transitioning to other programming languages more easily.

• Learning C first may prepare programmers better for understanding syntax rules in other languages compared to starting with simpler ones.

Relevance and Applications of C

• Despite being decades old, C remains relevant in job markets; many positions offer competitive salaries both nationally and internationally.

• It consistently ranks among the top 10 or 20 most sought-after programming languages each year, particularly in web and mobile systems development.

• Although there are newer frameworks tailored specifically for web/mobile applications, ongoing evolution in libraries could enhance its applicability in these areas.

Programming Logic Focus

• The course emphasizes learning programming logic using C as a foundational language applicable across various system types (desktop, web, mobile).

• While pure object-oriented support is absent in standard C, knowledge gained from this course will facilitate easier transitions into object-oriented paradigms found in languages like C++.

Development Environment Setup

• Students are encouraged to download the necessary development environment (IDE), which has an intuitive interface suitable for beginners.

• Basic programs written in C rely heavily on including libraries; understanding how to incorporate these is crucial for functionality within programs.

Practical Coding Insights

• The structure of a basic program includes defining functions where algorithms reside; students should familiarize themselves with this layout early on.

• Emphasis is placed on using command-line interfaces without graphical user interfaces (GUIs), reinforcing fundamental coding skills through text-based interactions.

Introduction to Programming Concepts

Understanding the Black Screen Interface

• The black screen, or terminal, is where users interact with the machine, viewing messages and inputting data.

• Users need to perform input and output operations to read messages from programs and enter text via the keyboard.

Utilizing Pre-programmed Functions

• The program will utilize pre-programmed input/output functions from the standard library (STD).

• Including #include <iostream> informs the program that it will use this library, which contains ready-to-use functions.

Main Function Structure

• The main function is defined as int main() , marking the entry point of the algorithm.

• Code within curly braces `` is executed by the machine; anything outside these braces is ignored.

Output Operations with Print Function

• The print function in programming outputs messages to the user on the terminal.

• Using printf("Hello World"), for example, displays "Hello World" on the screen—common practice for beginners.

Compiling and Executing Programs

• To execute a program, it must first be saved as a source file (e.g., hello_world.cpp) before compilation.

• Compilation transforms source code into an executable file (.exe), allowing it to run on a computer.

Running Compiled Programs

• After compiling successfully without errors, users can execute their program using specific commands or shortcuts (e.g., F10).

Understanding the Execution of a Simple Program

Overview of Program Execution

• The program prints characters sequentially, starting with 'h' and continuing until it reaches an exclamation mark, demonstrating how text is outputted on the screen.

• The execution time for the "Hello World" program is approximately 0.05 seconds, indicating a quick completion of tasks by the machine.

Process Termination and Return Codes

• Upon successful completion, the program returns a code of zero, signaling to the operating system that it has finished without errors.

• A non-zero return code would indicate an error in execution, whether due to syntax or semantic issues.

Compiling and Running Programs

• After compiling the program (using F9), a file named "hello world" is generated, which can be executed later.

• Executing via F10 invokes the compiled program; however, it runs so quickly that users may not see any output unless additional steps are taken.

Enhancing User Experience During Execution

• To allow users to see what happens during execution when running from Windows, adding System pause in the code helps keep the window open until a key is pressed.

• Including necessary libraries (like STD Lib.h) is essential for using certain functions like System pause.

Importance of Recompilation

• After modifying code (e.g., adding System pause), recompilation is crucial; failing to do so will result in executing outdated versions of programs.

• Successful recompilation allows for new instructions to take effect; otherwise, previous outputs will persist despite changes made in code.

Common Errors in Programming

Understanding Error Handling in Programming

Common Mistakes and Error Identification

• The speaker discusses the importance of recognizing when a point may have been forgotten or overlooked during coding, emphasizing that even if one is confident, errors can still occur.

• A specific example is provided where a missing semicolon leads to an error. The speaker highlights that the error message indicates the line number but may not always pinpoint the exact location of the mistake.

• The speaker notes that sometimes clicking on an error multiple times can lead to confusion about where the actual issue lies, as it might highlight a different line than expected.

• Emphasis is placed on checking lines immediately before the indicated error line, as this often reveals hidden mistakes like missing punctuation.

• The discussion includes how whitespace can be misleading; while it may appear irrelevant, it can affect code execution. An example involving print statements illustrates this point.

Overview of Programming Language Features

• The speaker provides a brief history of programming languages, discussing both positive and negative characteristics from various perspectives.