Discussion
What is the output of this C code?
#include <stdio.h>
int main()
{
int i = 10;
int *p = &i;
foo(&p);
printf("%d ", *p);
printf("%d ", *p);
}
void foo(int **const p)
{
int j = 11;
*p = &j;
printf("%d ", **p);
}
Answer: B
Correct answer: 11 11 Undefined-value
int **const p makes p itself constant while leaving *p modifiable, so *p = &j is legal and foo prints 11.
But j dies when foo returns, so the caller's pointer dangles. The first printf in main often still finds 11, because nothing has yet overwritten that stack slot - but the call itself uses the stack, so the second read may find anything. Every read after the return is undefined; only the timing makes the first appear to work.
No comment is present. Be the first to comment.
Loading…
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development