sizeof operator

We know that the sizeof(variable) returns the size of the variable and sizeof(pointer) returns the amount of memory that can be addressed  in bytes.

Try this program:

01	#include
02	#include

03	using namespace std;
04	void sz(int p[]){

05	cout<<"sz: "<<sizeof(p)<<"\n";
06	}

07	int main(){
08	int p[]={1,2,3,4};

09	cout<<"main: "<<sizeof(p)<<"\n";
10	sz(p);

11	cout<<"main: "<<sizeof(p)<<"\n";
12	cout<<"sizeof(p):"<<sizeof(p)<<"   sizeof(&p[0]):"<<sizeof(&p[0])<<"\n";

13	return 0;
14	}

Output you get will be:

1	main: 16
2	sz: 8

3	main: 16
4	sizeof(p):16   sizeof(&p[0]):8

int p[4];
we know that p points to the first element in the array so the sizeof(p) should return the size of the memory being addressed, and so p is same as &p[0] and so sizeof(p) and sizeof(&p[0]) should be same.But that is not the case, sizeof(p) gives the sizeof the array in bytes i.e sizeof(int)*4 in this case.