&
operator in c++(pointer 1st video):&
operator provides address of a mentioned variable. But it dont work for charecter type variables.
For int type:
int main(){
int intgr = 3;
cout<<&intgr;
}
For float type:
int main(){
float flat = 13.2;
cout<<♭
}
For cahr type:
int main(){
char charecter = 'A';
cout<<&charecter;
}
This will output A
, because if you pass address of a char type variable in cout<<
then it returns the stored object in variable itself.
Solution:
&charecter
has a type of char*
and we need to change it to void*
using typecasting. By doing that cout<<
dont get to know what type of address it is, so it prints the address.
int main(){
char charecter = 'A';
cout<<(void*)&charecter;
}
Pointer is a variable which stores address of another variable.
Data type of the pointer variable should be same as the main variable. Size of a Pointer variable:
The size of a pointer in C/C++ is not fixed. It depends upon different issues like Operating system, CPU architecture etc. Usually it depends upon the word size of underlying processor for example for a 32 bit computer the pointer size can be 4 bytes for a 64 bit computer the pointer size can be 8 bytes. So for a specific architecture pointer size will be fixed.
It is common to all data types like int *, float * etc.
PS: Read about ` Dereference Operator`.
int A[] = {2,4,5,8,9};
int *ptr;
prt = A
cout<<ptr<<" "<<A; // Address of A[2] -> the 1st element
cout<<*ptr // Prints the element stored in A[2],
//its called dereferencing
cout<< ptr+1; // prints the address of 2nd element
cout<<*(ptr+1) // prints the 2nd element
In array pointer, you stores the address of the 1st element by providing the array name(here its A
) in an pointer array. Then to access the other elements by incrementing the pointer and dereferencing it one by one (I mean *(p+1)
). Dereferencing means adding *
with a pointer variable. This helps to get the element stored.
void fun(int *arr,int n){
...
}
int main(){
fun(arr, n);
}
void fun(int *x){
...
}
int main(){
fun(&x);
}