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Curso de C++ Básico

Introducción

La historia de C++

Entorno de desarrollo

El proceso de compilación

Instalación en Windows

Instalación en Linux

Instalación en macOS

Conceptos básicos

Estructura básica de un programa en C++

Tipos de datos

Variables

Constantes y listas

Operadores

Entrada y salida de datos

Control de flujo

El condicional if

El condicional switch

Ciclo for

Ciclos while y do-while

Funciones

Qué son las funciones

La biblioteca estandar de C++

Próximos pasos

Continúa con el Curso Programación Orientada a Objetos en C++

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How do cycles work in C++?

Cycles are a fundamental tool in programming languages, and in C++ they allow us to iterate a block of code over a list or a numerical range. For example, if we want to perform an operation on each element of a list of numbers, cycles facilitate this repetitive process. Here I will guide you through the basics of for-cycles in C++.

What is a for loop?

A for loop is an instruction that allows you to repeatedly execute a block of code a specified number of times. In C++, this structure is useful for iterating over numeric ranges or over lists, allowing us to execute the same code multiple times efficiently.

Basic syntax of a for loop

The basic structure of a for loop in C++ is as follows:

for(int i = 0; i < 10;  i++) { // Code to execute}

Initialization: We declare and initialize a variable, usually int i = 0.
Condition: We evaluate a condition (e.g. i < 10) that must be true for the loop to continue.
Increment: We increment the value of the variable (e.g. i++ is i = i + 1).

Within the code block, we can use this variable for specific operations. For example, print its value at each iteration:

std::cout << i << std::endl;

How to iterate with a variable limit?

Sometimes, the limit of iterations is not a fixed number. We can use variables to set this limit, which adds flexibility to the loop.

int limit;std::cout << "Limit: ";std::cin >> limit;
for(int i = 0; i < limit;  i++) { std::cout << i << std::endl;}

With this structure, the program asks the user how many iterations to perform.

How to iterate over lists?

For cycles also help us to perform operations on each element of a list. Let's see how to multiply each element by two:

int list[] = {100, 200,  300};
for(int i = 0; i < sizeof(list)/sizeof(list[0]);  i++) { std::cout << list[i] * 2 << std::endl;}

Here, we use sizeof to determine the size of the list by dividing it by the size of an element in bytes.

How to break a for loop?

We can use the break statement to exit a for loop under certain conditions. For example, we want to stop when we find the number 200:

for(int i = 0; i < sizeof(list)/sizeof(list[0]);  i++) { if(list[i] == 200) break; std::cout << list[i] << std::endl;}

When the number 200 is encountered, the loop is interrupted thanks to the break instruction.

How can I practice?

A great way to practice is to do practical exercises that challenge you to implement what you have learned. For example, try writing a loop that only displays even numbers from a list using conditionals.

With these basics of C++ for loops, you are ready to continue exploring the possibilities this language has to offer. Keep learning and experimenting with these structures!

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chris_mlvz

4 years ago

Por si no lo conocian también existe el for range en c++

#include <iostream>

using namespace std;

int main(int argc, char const *argv[])
{
    int lista[] = {100, 200, 300};
    for (auto &&i : lista)
    {
        cout << i << endl;
    }

    return 0;
}

Eliaz Bobadilla

4 years ago

Les dejo el código y el reto 😃

Parte Uno:

#include <iostream>

using namespace std;

int main() {
  int limit;
  cout << "Enter the max number: ";
  cin >> limit;
  for (int i = 0; i <= limit; i++) {
    cout << i << endl;
  }
}

Parte Dos:

#include <iostream>

using namespace std;

int main() {
  int list[] = {1, 20, 25};
  int limit = sizeof(list) / sizeof(list[0]);
  for (int i = 0; i < limit; i++) {
    cout << list[i] << endl;
  }
}

El Reto:

#include <iostream>

using namespace std;

int main() {
  int limit;
  cout << "Enter the max number: ";
  cin >> limit;

  for (int i = 1; i < limit; i++) {
    if (i % 2 == 0) {
      cout << i << endl;
    }
  }
}

Se les ocurre otra solución?

Emilio Jesus Nuñez Pineda

4 years ago

Tuve que investigar un poco para el reto, ya que no conocia del modulo %.

#include <iostream> // obtener datos de entrada o de salida
using namespace std; //te permite utilizar, en el código, 
                        //nombres estandar de c++, para poder importarlas 
                        //sin necesidad de escribir desde donde la estamos importando
//mostrar solo los numeros pares
int main() {
    int limit;
    cout << "Introduzca su valor maximo: ";
    cin >> limit;
    for (int i = 2; i < limit; i++)
    {
        if(i % 2 == 0)
        {
            cout << i << endl;
        }
    }
}

Brayan Segovia

4 years ago

#include <iostream>

using namespace std; 

int main(){
	int numbers[] = { 
	1, 	2,	3,	4,	5,	6,	7,	8,	9,	10,
	11,	12,	13,	14,	15,	16,	17,	18,	19,	20,
	21,	22,	23,	24,	25,	26,	27,	28,	29,	30,
	31,	32,	33,	34,	35,	36,	37,	38,	39,	40,
	41,	42,	43,	44,	45,	46,	47, 48,	49,	50,
	51,	52,	53,	54,	55,	56,	57,	58,	59,	60,
	61,	62,	63,	64,	65,	66,	67,	68,	69,	70,
	71,	72,	73,	74,	75,	76,	77,	78,	79,	80,
	81,	82,	83,	84,	85,	86,	87,	88,	89,	90,
	91,	92,	93,	94,	95,	96,	97,	98,	99,	100 };
	
	int limite = sizeof(numbers)/sizeof(numbers[0]);
	for(int i = 0; i < limite ; i++){
		if(numbers[i]%2==0){
			cout<< numbers[i] << endl;
		}
	}
}