Cuando una variable se declara como referencia, se convierte en un nombre alternativo para una variable existente. Una variable se puede declarar como referencia poniendo ‘&’ en la declaración.
CPP
#include <iostream>
using namespace std;
int main()
{
int x = 10;
// ref is a reference to x.
int& ref = x;
// Value of x is now changed to 20
ref = 20;
cout << "x = " << x << '\n';
// Value of x is now changed to 30
x = 30;
cout << "ref = " << ref << '\n';
return 0;
}
Producción:
CPP
#include <iostream>
using namespace std;
void swap(int& first, int& second)
{
int temp = first;
first = second;
second = temp;
}
int main()
{
int a = 2, b = 3;
swap(a, b);
cout << a << " " << b;
return 0;
}
CPP
struct Student {
string name;
string address;
int rollNo;
}
// If we remove & in below function, a new
// copy of the student object is created.
// We use const to avoid accidental updates
// in the function as the purpose of the function
// is to print s only.
void print(const Student &s)
{
cout << s.name << " " << s.address << " " << s.rollNo
<< '\n';
}
CPP
#include <bits/stdc++.h>
using namespace std;
int main()
{
vector<int> vect{ 10, 20, 30, 40 };
// We can modify elements if we
// use reference
for (int& x : vect) {
x = x + 5;
}
// Printing elements
for (int x : vect) {
cout << x << " ";
}
cout << '\n';
return 0;
}
CPP
#include <bits/stdc++.h>
using namespace std;
int main()
{
vector<string> vect{ "geeksforgeeks practice",
"geeksforgeeks write",
"geeksforgeeks ide" };
// We avoid copy of the whole string
// object by using reference.
for (const auto& x : vect) {
cout << x << '\n';
}
return 0;
}
C++
#include <iostream>
using namespace std;
int main()
{
int i = 10; // simple or ordinary variable.
int* p = &i; // single pointer
int** pt = &p; // double pointer
int*** ptr = &pt; // triple pointer
// All the above pointers differ in the value they store
// or point to.
cout << "i = " << i << "\t"
<< "p = " << p << "\t"
<< "pt = " << pt << "\t"
<< "ptr = " << ptr << '\n';
int a = 5; // simple or ordinary variable
int& S = a;
int& S0 = S;
int& S1 = S0;
cout << "a = " << a << "\t"
<< "S = " << S << "\t"
<< "S0 = " << S0 << "\t"
<< "S1 = " << S1 << '\n';
// All the above references do not differ in their
// values as they all refer to the same variable.
}
CPP
#include <iostream>
using namespace std;
int& fun()
{
static int x = 10;
return x;
}
int main()
{
fun() = 30;
cout << fun();
return 0;
}
CPP
#include <iostream>
using namespace std;
int fun(int& x) { return x; }
int main()
{
cout << fun(10);
return 0;
}
CPP
#include <iostream>
using namespace std;
void swap(char*& str1, char*& str2)
{
char* temp = str1;
str1 = str2;
str2 = temp;
}
int main()
{
char* str1 = "GEEKS";
char* str2 = "FOR GEEKS";
swap(str1, str2);
cout << "str1 is " << str1 << '\n';
cout << "str2 is " << str2 << '\n';
return 0;
}
CPP
#include <iostream>
using namespace std;
int main()
{
int x = 10;
int* ptr = &x;
int&* ptr1 = ptr;
}
CPP
#include <iostream>
using namespace std;
int main()
{
int* ptr = NULL;
int& ref = *ptr;
cout << ref << '\n';
}
CPP
#include <iostream>
using namespace std;
int& fun()
{
int x = 10;
return x;
}
int main()
{
fun() = 30;
cout << fun();
return 0;
}
Publicación traducida automáticamente
Artículo escrito por GeeksforGeeks-1 y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA