Reason behind error?

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C++

#include<iostream>
using namespace std;
typedef struct student stud
{
    int rno;
    stud *s;
}
int main()
{
    s->rno=30;
    cout<<s->rno;
    return 0;
}

What I have tried:

is this program showing error because we can't give an alternative name to a memory before its existence.If this is the the case then we couldn't have been able to use typedef even after structure definition, since a structure memory is created when it's variable is created?
my question is:
is it possible to create self-refrential structure using typedef keyword?

Posted 10-Sep-17 6:31am

Member 13057504

Updated 10-Sep-17 7:20am

CPallini

v2

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[no name] 10-Sep-17 12:44pm

"is it possible to create self-refrential structure using typedef keyword":
Yes it is possible. But your code is responsible to allocate/deallocate stud *s;

Richard MacCutchan 10-Sep-17 14:52pm

You have not declared a variable with the name s.

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CPallini · Answer 1 · 2017-09-10T07:20:00

The program is showing errors because there are errors...
Please note you don't need to typedef structs in C++.
Try

C++

#include<iostream>
using namespace std;

struct stud
{
    int rno;
    stud *s;
};

int main()
{
    stud * s = new stud();
    s->rno=30;
    s->s = nullptr;
    cout << s->rno <<endl;
    delete s;

    return 0;
}