My program does not print anything and fails

Question

My program does not print anything and fails.

#include <stdio.h>

struct data{
int giorno, mese, anno;
};
struct data d, *p;

int main(void){ 

    p->giorno = 15;
    p->mese = 8;
    p->anno = 2005;
    printf("%d", p->giorno );
}

OUTPUT:

Process exited after 0.2837 seconds with return value 3221225477 Press any key to continue. . .

A few links that provide basic discussions of pointers may help. [Difference between char *pp and (char*) p?](https://stackoverflow.com/a/60519053/3422102) and [Pointer to pointer of structs indexing out of bounds(?)...](https://stackoverflow.com/a/60639540/3422102) (ignore the titles, the answers discuss pointer basics) — David C. Rankin, May 13 '21 at 08:02

score 0 · Accepted Answer · edited May 16 '21 at 12:09

0

The variable p doesn't point to anywhere. The memory there is just garbage value. So, either do:

p = malloc(sizeof(struct data));

This will allocate some memory on the heap and store the address in p.

Or,

p = &<some valid memory>;

I think you intended to do:

p = &d;

Which would store the address of d in p.

edited May 16 '21 at 12:09

Peter Mortensen

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answered May 13 '21 at 08:02

Shambhav

813
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20

score 0 · Answer 2 · edited May 16 '21 at 12:10

0

If your intention is to put data in a struct there isn't any need for a pointer. Just use:

#include <stdio.h>

struct data{
    int giorno, mese, anno;
};
struct data d;

int main(void){

    d.giorno = 15;
    d.mese = 8;
    d.anno = 2005;
    printf("%d", d.giorno);
}

edited May 16 '21 at 12:10

Peter Mortensen

30,738
21
105
131

answered May 13 '21 at 08:26

Elior Kanfi

31
5

My program does not print anything and fails

OUTPUT:

2 Answers2