Hello everybody!
Recently while i was experimenting with some code written in c++ i noticed something that confused me a bit. In that code i had to deal with 2 structs :

struct date
{
    string day;
    int month; 
    int dday;
   int year; };

and the other struct

struct note
{
     date d;
     string notice;  };

I noticed that when i was passing in a function i built, an instance of note struct as a pointer parameter my program kept crashing continuously, although compiler wasn't complaining. To make myself clear :

void myFunction(note* n, ...other parameters...)
{
    cout << n->d.day << endl;
   cout << n->d.month << endl;
    etc...
}

I'm sure that my program crashed because of that piece of code

n->d.day

i'm sure because i tested it in debug mode.
When i wrote my function differently i had no problem running my program :

void myFunction(note& n, ..other parameters...)
{
    cout << n.d.day << endl;
    cout << n.d.month << endl;
  etc...
  }

Has anyone got an idea why the pointer parameter and the arrow
caused that problem? Looking forward to reading your ideas and thoughts...Thank you in advance for your time...

vanalex

Thank you very much tux4life, it didn't even cross my naive mind...

vanalex

Thanks God, -> and . have the same precedence and associativity.
The OP example with a pointer parameter works fine in VC++ 2008.
Diagnosis: insufficient info ;)

As already pointed out, the . and -> have the same precidence. Also, they are L-to-R associative, so you did not need the parenthesis (other than to make it simpler to understand).

It looks to me like your function header is using old-fashioned C method for passing something "by reference", but I am guessing that the function call is not doing its part.

function myFunc (struct note *x) // C style - x is ptr to a struct note
{
   ...
}

struct note n;
myFunc(&n); // C style - pass a copy of ptr to n

C++ provides a way to avoid the reference/dereference dance on the function call/function definition that we had to do in C to simulate "call-by-reference". It did so by introducing the prefix operator, &, for parameters in the parameter list of the function definition to mean call-by-reference. This has a different meaning than other contexts for a unary-& (such as the one above in the function call argument). C++ was able to introduce this new way to use the & because the unary-& was invalid (in C) in a parameter list so there was no ambiguity in adding this.

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