main()
{
char *p1="Name";
char *p2;
p2=(char *)malloc(20);
while(*p2++=*p1++);
printf("%s\n",p2);
}
what is the output?
Answer Posted / vadivel t
Hi all,
#1 Mannucse's ans is wrong. cos as mentioned "Name" will
not be the output.
#2 Sanath's ans is wrong. Cos at the end of the while loop,
p2 will not point to NULL. It will point to the next byte
to the NULL termination ie., 6th byte.
#3 Shruti's ans is wrong. cos i think she got confused
between assignment(=) and comparisonal(==) operators. And
the statement given as "we cannot copy the value of p1 in
p2, the way its mentioned here" is absolutely wrong.
So,
Lets Analyse the program and how to get the required output.
hav a look on th program again.
main()
{
char *p1="Name";
char *p2;
p2=(char *)malloc(20);
while(*p2++ = *p1++)
{
printf("TEST \n");
}
printf("%s\n",p2);
getch();
}
Here, in every iteration of while loop, we are assigning
*p1 to *p2, and incrementing both pointers p1 and p2, After
completion(when *p1 value would be '\0')of the while loop,
first 5 bytes of p2 holds the
characters 'N','a','m','e' '\0'. At the end of while loop
p2 points to the 6th byte in the memory.
So, now printf("%s\n",p2); shall start print the values
from the 6th byte to 20th bytes of the memory which was
allocated dynamically.
----------------------------------
To get the desired output change the printf statement to
printf("%s\n",p2-5);
Now (p2-5) points to the starting address of p2 and will
print the values in the memory till it encounters '\0'
termination. ie., The output would be -> Name
| Is This Answer Correct ? | 9 Yes | 6 No |
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