23 Jan C++ Pointers
The C++ Pointer is a variable that is used to store the memory address as its value. However, to get the memory address of a variable, use the & operator. This means a variable has a unique memory location. This memory location has its own address. To access this address, we use the ampersand i.e., the & operator.
In this lesson, we will discuss the two operators useful to understand the concept of Pointers in C++:
- The Address Operator: Access the address of a variable. Defined by &, the ampersand sign.
- The Indirection Operator: Access the value of an address. Defined by *, the asterisk sign.
Let us see an example to display the address of variables in C++:
#include <iostream>
#include <string>
using namespace std;
int main() {
int a;
float b;
char c;
string d = "Demo";
cout <<"Address of variable a = "<<&a;
cout <<"\nAddress of variable b = "<<&b;
cout <<"\nAddress of variable c = "<<&c;
cout <<"\nAddress of variable d = "<<&d;
return 0;
}
Output
Address of variable a = 0x7ffe94acce58 Address of variable b = 0x7ffe94acce5c Address of variable c = 0x7ffe94acce83 Address of variable d = 0x7ffe94acce60
Pointers Syntax
The following is the syntax of Pointers in C++:
dataType *varName;
Above, varName is the pointer variable, whereas datatype is the type.
Declare and create a Pointer
Follow the above syntax and let us see how we can create and declare pointers to different types.
Pointer to Integer
int* a;
Pointer to Float
float* b;
Pointer to Char
char* c
Ways to Declare Pointers in C++
We can declare Pointers in any of the following three ways. Only a single way was demonstrated above:
int* a; int *a; int * a; float* b; float *b; float * b; char* c char *c char * c
Pointer – Examples
After understanding the above concept, let us now move further and work around Pointer Examples in C++.
Pointer to Integer
The 1st example is to create a pointer variable and point to an integer variable:
#include <iostream>
using namespace std;
int main() {
// Our integer variable i
int i = 10;
// A pointer variable j storing the address of the variable i
int* j = &i;
cout <<"Integer Value = "<<i;
cout <<"\nThe memory address of the variable str = "<<&i;
cout <<"\nDisplays the memory address of the variable i with the pointer = "<<j;
return 0;
}
Output
Integer Value = 10 The memory address of the variable str = 0x7fff1fe951f4 Displays the memory address of the variable i with the pointer = 0x7fff1fe951f4
Pointer to String
The 2nd example is to create a pointer variable and point to a string variable:
#include <iostream>
#include <string>
using namespace std;
int main() {
// Our string variable str
string str = "Amit";
// A pointer variable p storing the address of the variable str
string* p = &str;
cout <<"String Value = "<<str;
cout <<"\nThe memory address of the variable str = "<<&str;
cout <<"\nDisplays the memory address of the variable str with the pointer = "<<p;
return 0;
}
Output
String Value = Amit The memory address of the variable str = 0x7ffcda214900 Displays the memory address of the variable str with the pointer = 0x7ffcda214900
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