The pointer in C++ language is a variable, it is also known as locator or indicator that points to an address of a value.
There are many usage of pointers in C++ language.
In c language, we can dynamically allocate memory using malloc() and calloc() functions where pointer is used.
Pointers in c language are widely used in arrays, functions and structures. It reduces the code and improves the performance.
| Symbol | Name | Description |
|---|---|---|
| & (ampersand sign) | Address operator | Determine the address of a variable. |
| ∗ (asterisk sign) | Indirection operator | Access the value of an address. |
The pointer in C++ language can be declared using ∗ (asterisk symbol).
int ∗ a; //pointer to int char ∗ c; //pointer to char
Let's see the simple example of using pointers printing the address and value.
#include <iostream>
using namespace std;
int main()
{
int number=30;
int ∗ p;
p=&number;//stores the address of number variable
cout<<"Address of number variable is:"<<&number<<endl;
cout<<"Address of p variable is:"<<p<<endl;
cout<<"Value of p variable is:"<<*p<<endl;
return 0;
}Pointer Program to swap 2 numbers without using 3rd variable
#include <iostream>
using namespace std;
int main()
{
int a=20,b=10,∗p1=&a,∗p2=&b;
cout<<"Before swap: ∗p1="<<∗p1<<" ∗p2="<<∗p2<<endl;
∗p1=∗p1+∗p2;
∗p2=∗p1-∗p2;
∗p1=∗p1-∗p2;
cout<<"After swap: ∗p1="<<∗p1<<" ∗p2="<<∗p2<<endl;
return 0;
}
