Punteros en C/C++ con ejemplos

Los punteros son representaciones simbólicas de direcciones. Permiten que los programas simulen llamadas por referencia, así como que creen y manipulen estructuras de datos dinámicas. Su declaración general en C/C++ tiene el formato:

Sintaxis:

// C++ program to illustrate Pointers in C++
#include <stdio.h>
  
void geeks()
{
    int var = 20; 
      
    // declare pointer variable    
    int *ptr; 
      
    // note that data type of ptr and var must be same
    ptr = &var;    
  
    // assign the address of a variable to a pointer
    printf("Value at ptr = %p \n",ptr);
    printf("Value at var = %d \n",var);
    printf("Value at *ptr = %d \n", *ptr);     
}
  
// Driver program
int main()
{
    geeks();
}

// C++ program to illustrate Pointers in C++
  
#include <bits/stdc++.h>
using namespace std;
void geeks()
{
    int var = 20; 
      
        //declare pointer variable    
    int *ptr; 
      
    //note that data type of ptr and var must be same
    ptr = &var;    
  
    // assign the address of a variable to a pointer
    cout << "Value at ptr = " << ptr << "\n";
    cout << "Value at var = " << var << "\n";
    cout << "Value at *ptr = " << *ptr << "\n";     
}
//Driver program
int main()
{
    geeks();
}

// C program to illustrate call-by-methods
#include <stdio.h>
  
void geeks() 
{ 
    //Declare an array 
    int val[3] = { 5, 10, 20 }; 
      
    //declare pointer variable 
    int *ptr; 
      
    //Assign the address of val[0] to ptr 
    // We can use ptr=&val[0];(both are same) 
    ptr = val ; 
    printf("Elements of the array are: "); 
    printf("%d %d %d", ptr[0], ptr[1], ptr[2]); 
} 
//Driver program 
int main() 
{ 
    geeks(); 
}

// C++ program to illustrate Array Name as Pointers in C++
#include <bits/stdc++.h>
using namespace std;
void geeks()
{
    //Declare an array
    int val[3] = { 5, 10, 20 };
      
    //declare pointer variable 
    int *ptr;
      
    //Assign the address of val[0] to ptr
    // We can use ptr=&val[0];(both are same)
    ptr = val ;
    cout << "Elements of the array are: ";
    cout << ptr[0] << " " << ptr[1] << " " << ptr[2];
}
//Driver program
int main()
{
    geeks();
}