CASE 1:
#include <stdio.h>
int main()
{
int a = 5,*p;
*p = &a;
printf("%d",*p);
}
the above mentioned program gives the segmentation fault problem. but in the case 2 it works fine. CASE 2:
#include <stdio.h>
int main()
{
int a = 5,*p = &a;
printf("%d",*p);
}
can anyone please explain this problem. Thank you.
*p = &a;
Dereferences p
and assigns &a
to the memory location p
is pointing to . The pointer is uninitialized, so dereferencing it yields undefined behavior (thus the segmentation fault).
int a = 5,*p = &a;
Defines a
and p
, where the asterisk doesn't indicate dereferencing but distinguishes a usual int
definition from a int*
pointer definition. The line is equivalent to
int a = 5;
int* p = &a;
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