Compare the behavior of both t

Interview Question

0

of 0 votes

10
Answers
Compare the behavior of both the programs :
(1) . #include<stdio.h>
int main()
{
int i,a[3];
for(i=0;i<=3;i++)
a[i]=1;
for(i=0;i<=3;i++)
printf("%d\n",a[i]);
return 0;
}

(2) . #include<stdio.h>
int main()
{
int i,a[3];
for(i=0;i<=3;i++)
a[i]=i;
for(i=0;i<=3;i++)
printf("%d\n",a[i]);
return 0;
}
- Shobhit July 05, 2012 in United States | Report Duplicate | Flag | PURGE
C

Email me when people comment.

An error occurred in subscribing you.

Country: United States

Email me when people comment.

An error occurred in subscribing you.

Comment hidden because of low score. Click to expand.

of 0 vote

your array is of size 3 but you are storing 4 items in it. so the compiler seems to throwing an error - stack around the variable is corrupted.
as such the first code prints
1
1
1
1

and the second one prints
0
1
2
3

- Anonymous July 05, 2012 | Flag Reply

Comment hidden because of low score. Click to expand.

of 0 votes

i've executed both the programs on gcc .
second prog is giving o/p 0 1 2 3
but first one is neither showing any o/p neither any an error . Cursor remain static .

- Shobhit July 05, 2012 | Flag

Comment hidden because of low score. Click to expand.

of 0 votes

i guess it depends on the compiler too. I got the output in microsofts c++ compiler in visual studio 2010 along with the error.

however in gcc in unix i seem to having the exact same output as yours.

- Anonymous July 05, 2012 | Flag

Comment hidden because of low score. Click to expand.

of 0 votes

But what could be the possible reason ??
Changing i to 1 changes the pattern of whole output .

- Shobhit July 05, 2012 | Flag

Comment hidden because of low score. Click to expand.

of 0 votes

Stackoverflow has a nice thread on the dangers of errors arising due to exceeding the bounds of arrays.

stackoverflow.com/questions/1239938/c-accesses-an-array-out-of-bounds-gives-no-error-why

- Anonymous July 05, 2012 | Flag

Comment hidden because of low score. Click to expand.

of 0 vote

out of index.
stack will overflow, so last a[3] will overwrite to buffer of variable 'i' on some O/S.
Anyway, the result is;
(1)
1
1
1
1

(2)
0
1
2
3

- und3r July 05, 2012 | Flag Reply

Comment hidden because of low score. Click to expand.

of 0 votes

plz . run the first prog on gcc .

- Shobhit July 05, 2012 | Flag

Comment hidden because of low score. Click to expand.

of 0 votes

you run it in visual studio 2010 it's giving answer 1 1 1 1 and 0 1 2 3

- kk July 05, 2012 | Flag

Comment hidden because of low score. Click to expand.

of 0 vote

out of bound error
int a[3] means three elements a[0],a[1], a[2]
for(i=0;i<=3;i++) will throw error for trying a[3]

- Anonymous July 06, 2012 | Flag Reply

Comment hidden because of low score. Click to expand.

of 0 vote

the question wont run properly....
it will return a segmentation fault..
instead change the array declaration to int a[4]
and then use
for(i=0;i<=3;i++)
a[i]=i;
it will emit the output
1
1
1
1

- Anonymous July 08, 2012 | Flag Reply

CareerCup

Interview Question

Books

Videos

Resume Review

Mock Interviews