Sintaxis basica

Initial project setup in C++

In C++ you usually work with files and a project folder structure. To start (and to grow without chaos), use one of these two setups:

Option 1: single file (for practice)

• Create a folder, e.g. my-project/
• Inside it, create main.cpp

Structure:

my-project/
  main.cpp

Option 2: typical structure (recommended)

Structure:

my-project/
  CMakeLists.txt
  src/
    main.cpp
    greeting.cpp
  include/
    greeting.h

• src/: source code (.cpp)
• include/: headers (.h) with declarations (what a function/class “promises”)
• CMakeLists.txt: build configuration file for CMake

Minimal program (and what each part means)

#include <iostream>

int main() {
    std::cout << "Hola C++" << std::endl;
    return 0;
}

Line-by-line explanation

• #include <iostream>: imports the standard input/output library so you can use std::cout.
  • <> means it’s a standard library header.
• int main(): program entry point. Most console programs start here.
  • int means the function returns an integer to the operating system.
• { ... }: braces define the block of code that belongs to main.
• std::cout: output to the console (terminal).
• <<: “insertion” operator used to send data into cout.
• std::endl: newline + flush. You can also use "\n" in many cases.
• ; (semicolon): ends a statement.
• return 0;: means “finished successfully”. (Modern C++ compilers often assume 0 if omitted in main, but we keep it explicit here.)

Basic syntax rules (common beginner pitfalls)

• Case matters: Main is not the same as main.
• Most statements end with ; (except constructs like if (...) {}).
• Braces control structure: they define what belongs to an if, for, while, functions, classes, etc.
• Indentation: doesn’t change meaning, but it makes code readable. Use 2 or 4 spaces consistently.

Comments (to explain your code)

// Single-line comment

/*
  Multi-line
  comment
*/

Variables and types (quick base)

int age = 20;           // integer
double pi = 3.14159;    // floating point
char letter = 'A';      // one character
bool active = true;     // true/false

Conditionals (if / else)

int grade = 15;

if (grade >= 10) {
    std::cout << "Passed\n";
} else {
    std::cout << "Failed\n";
}

Loops (for / while)

for (int i = 0; i < 5; i++) {
    std::cout << i << "\n";
}

int j = 0;
while (j < 5) {
    std::cout << j << "\n";
    j++;
}

Build your first project (with CMake)

If you’re using the recommended structure, create a minimal CMakeLists.txt like this:

cmake_minimum_required(VERSION 3.16)
project(my_project LANGUAGES CXX)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

add_executable(my_project
  src/main.cpp
)

Then, in a terminal inside your project folder:

cmake -S . -B build
cmake --build build

This will generate the executable inside build/ (exact name/location depends on your OS).

Agrega aqui operadores, condicionales, ciclos y ejemplos de clase.