Question

I’m getting a compile error

“conversion from ‘int*’ to non-scalar type ‘foo< int>’ requested”

What am i doing wrong?

template <typename T> 
struct foo {
  T *ptr;
  foo(void){}
  foo<T>& operator =(const T &point) {
    if (ptr != &point) {
  ptr = &point;
    }
    return *this;
  }
  T& operator*() {
    return *ptr;
  }
}

int main(){
  int x;        
  foo<int> f = &x;  //error here
  *f = 0;
  printf("%d\n", *f)
}

Answer 1

The problem on the line indicated is that you have type mismatch between the variable f and its initializer:

foo<int> f = &x;

The variable has type foo<int> while the initializer is of type int* and foo<int> doesn’t have a constructor taking an int* as argument. Note that the equal sign in variable definition indicates initialization, not assignment.

Note that the code has more problems, though. Many of them are related to inconsistent use of the ptr identifier (sometimes as a member variable, sometimes as a function, sometimes as a type), to invalid use of & and more type mismatch errors.