Creating Pointers
You learned from the previous chapter, that we can get the memory address of a variable by using the & operator:
Example
string food = "Pizza";
// A food variable of type string cout << food; // Outputs the value of food (Pizza) cout << &food; // Outputs the memory address of food ( 0x6dfed4 )A pointer however, is a variable that stores the memory address as its value .
A pointer variable points to a data type (like int or string ) of the same type, and is created with the * operator. The address of the variable you're working with is assigned to the pointer:
Example
string food = "Pizza"; // A food variable
of type string
string* ptr = &food;
// A pointer variable, with the name ptr, that stores the address of food // Output the value of food (Pizza) cout << food << "\n"; // Output the memory address of food (0x6dfed4) cout << &food << "\n"; // Output the memory address of food with the pointer (0x6dfed4) cout << ptr << "\n";Create a pointer variable with the name ptr , that points to a string variable, by using the asterisk sign * ( string* ptr ). Note that the type of the pointer has to match the type of the variable you're working with.
Use the & operator to store the memory address of the variable called food , and assign it to the pointer.
Now, ptr holds the value of food 's memory address.
Tip
There are three ways to declare pointer variables, but the first way is preferred:
string* mystring; // Preferred
string *mystring;
string * mystring;