Categories:
.NET (357)
C (330)
C++ (183)
CSS (84)
DBA (2)
General (7)
HTML (4)
Java (574)
JavaScript (106)
JSP (66)
Oracle (114)
Perl (46)
Perl (1)
PHP (1)
PL/SQL (1)
RSS (51)
Software QA (13)
SQL Server (1)
Windows (1)
XHTML (173)
Other Resources:
Using Pointers
What print out will the folloging code produce?
main() {
char *p1=“name”;
char *p2;
p2=(char*)malloc(20);
memset (p2, 0, 20);
while(*p2++ = *p1++);
printf(“%s\n”,p2);>
}
✍: Guest
The pointer p2 value is also increasing with p1
.
*p2++ = *p1++ means copy value of *p1 to *p2 , then
increment both addresses (p1,p2) by one , so that they
can point to next address . So when the loop exits (ie
when address p1 reaches next character to “name” ie
null) p2 address also points to next location to
“name” . When we try to print string with p2 as
starting address , it will try to print string from
location after “name” … hense it is null string ….
eg :
initially p1 = 2000 (address) , p2 = 3000
*p1 has value "n" ..after 4 increments , loop exits …
at that time p1 value will be 2004 , p2 =3004 … the
actual result is stored in
3000 - n , 3001 - a , 3002 - m , 3003 -e … we r trying
to print from 3004 …. where no data is present … thats
why its printing null .
Answer:empty string.
2007-02-26, 7538👍, 0💬
Popular Posts:
Where Is the Submitted Form Data Stored? - PHP Script Tips - Processing Web Forms When a user submit...
Enable ASP.NET polling using “web.config” file Now that all our database side is configured in order...
Can you have virtual functions in Java? Yes, all functions in Java are virtual by default. This is a...
How To Select Some Rows from a Table? - MySQL FAQs - SQL SELECT Query Statements with GROUP BY If yo...
What Is the Text Paragraph Formatting Model? - CSS Tutorials - HTML Formatting Model: Block, Inline ...