Passing pointer to a function in C++ -

i wrote following piece of code

#include <iostream>  using namespace std;  void temp (int * x) {     x=new int [2];     x[0]=1;     x[1]=2; }  int main() {     int *ptr;     temp(ptr);     cout<<ptr[0]<<endl;     cout<<ptr[1]<<endl;     return 0; } 

running gives seg fault, memory allocation happens inside temp function local function? memory gets deallocated while returning temp? know, solve problem, need pass pointer pointer ptr, still, why thing not work?

to alter in function in c, need pass pointer it. in case, want alter pointer, need pointer pointer:

void temp (int** x) 

then in function use *x have x (you need (*x)[n], *x[n] means else)

then call temp with:

temp(&ptr); 

this should solve in c, , work in c++.

in c++, pass reference pointer:

 void temp(int*&x) 

which allow syntax have used unchanged.