C Questions on Pointers - Revision history

Arjun Suresh at 20:18, 16 June 2014

2014-06-16T20:18:52Z

Arjun Suresh at 19:53, 16 June 2014

2014-06-16T19:53:41Z

Arjun Suresh at 19:53, 16 June 2014

2014-06-16T19:53:03Z

Arjun Suresh at 19:52, 16 June 2014

2014-06-16T19:52:41Z

Arjun Suresh at 19:52, 16 June 2014

2014-06-16T19:52:19Z

Arjun Suresh at 19:51, 16 June 2014

2014-06-16T19:51:59Z

Arjun Suresh at 19:50, 16 June 2014

2014-06-16T19:50:22Z

Arjun Suresh at 21:46, 15 June 2014

2014-06-15T21:46:49Z

Arjun Suresh at 21:38, 15 June 2014

2014-06-15T21:38:59Z

Arjun Suresh: Created page with " {'''What will be the output of the following code?''' #include int main(){ int a = 5; int* p = &a; printf("%..."

2014-06-15T21:04:37Z

Created page with "<quiz display="simple"> {'''What will be the output of the following code?''' <syntaxhighlight lang="c"> #include<stdio.h> int main(){ int a = 5; int* p = &a; printf("%..."

New page

<quiz display="simple">
{'''What will be the output of the following code?'''
<syntaxhighlight lang="c">
#include<stdio.h>

int main(){
int a = 5;
int* p = &a;
printf("%d", ++*p);

}
</syntaxhighlight>
|type="{}"
/}
{ 6 }
||p is pointing to the address of a. *p will return the content of a which is 5 and ++ will increment it to 6.

{'''What will be the output of the following code?'''
<syntaxhighlight lang="c">
#include<stdio.h>

int main(){
char a[] = "Hello World";
char* p = &a;
printf("%s", p+2 );

}
</syntaxhighlight>
|type="()"
/}
-Compiler Error
-World
+llo World
-Runtime Error

||Since p is a char pointer p+2 will add 2 to p (since sizeof(char) is 1). So, p+2 will be pointing to the string "llo World"

{'''What will be the output of the following code?'''
<syntaxhighlight lang="c">
#include<stdio.h>

int main(){
int a;
int* p = &a;
printf("%zu", sizeof( *(char*)p ));

}
</syntaxhighlight>
|type="()"
/}

+1
-2
-4
-Compile Error

||p is typecasted to char pointer and then dereferenced. So, returned type will be char and sizeof(char) is 1

</quiz>

@@ Line 88: / Line 88: @@
+{
    int *a = (int*) 1;
- printf("%d", a);
+  printf("%d", a);
+}
 </syntaxhighlight>
@@ Line 107: / Line 107: @@
+{
    int a = 1, *p, **pp;
- p = &a;
+  p = &a;
- pp = p;
+  pp = p;
- printf("%d", **pp);
+  printf("%d", **pp);
+}
 </syntaxhighlight>
@@ Line 127: / Line 127: @@
+{
    int a = 1, *p, **pp;
- p = &a;
+  p = &a;
- pp = p;
+  pp = p;
- printf("%d", *pp);
+  printf("%d", *pp);
+}
 </syntaxhighlight>

@@ Line 93: / Line 93: @@
 |type="()"
 /}
-- 0
+-Garbage value
 +1
 -0
@@ Line 114: / Line 114: @@
 |type="()"
 /}
--0
+-Garbage value
 -1
 -Compile error
@@ Line 135: / Line 135: @@
 /}
 +1
--2
+-Garbage value
 -Compile error
 -Segmentation fault

@@ Line 114: / Line 114: @@
 |type="()"
 /}
 -1
 -Compile error
 +Segmentation fault

@@ Line 135: / Line 135: @@
 /}
 +1
--0
+-2
 -Compile error
 -Segmentation fault

@@ Line 35: / Line 35: @@
 -Runtime Error
-||Since p is a char pointer p+2 will add 2 to p (since sizeof(char) is 1). So, p+2 will be pointing to the string "llo World"
+||Since p is a char pointer p+2 will add 2 to p (since sizeof(char) is 1). So, p+2 will be pointing to the string "llo World".
 {'''What will be the output of the following code?'''
@@ Line 56: / Line 56: @@
 -Compile Error
-||p is typecasted to char pointer and then dereferenced. So, returned type will be char and sizeof(char) is 1
+||p is typecasted to char pointer and then dereferenced. So, returned type will be char and sizeof(char) is 1.
 {'''Is the following code legal?'''
@@ Line 79: / Line 79: @@
 +Yes
 -No
-||On a little endian machine the lower address will contain the least significant byte. Suppose a is stored at address 1000 and contains 1, then character at 1000 will be 1, if the machine is little endian
+||On a little endian machine the lower address will contain the least significant byte. Suppose a is stored at address 1000 and contains 1, then character at 1000 will be 1, if the machine is little endian.

@@ Line 79: / Line 79: @@
 +Yes
 -No
 {'''Assuming a little endian machine, what will be the output of the following program?'''
@@ Line 113: / Line 115: @@
 -Runtime error
 -Compiler dependent output
 </quiz>

@@ Line 4: / Line 4: @@
 #include<stdio.h>
-int main(){
+int main()
    int a = 5;
    int* p = &a;
    printf("%d", ++*p);
+}
 </syntaxhighlight>
@@ Line 21: / Line 21: @@
 #include<stdio.h>
-int main(){
+int main()
    char a[] = "Hello World";
    char* p = &a;
    printf("%s", p+2 );
+}
 </syntaxhighlight>
@@ Line 41: / Line 41: @@
 #include<stdio.h>
-int main(){
+int main()
    int a;
    int* p = &a;
    printf("%zu", sizeof( *(char*)p  ));
+}
 </syntaxhighlight>
@@ Line 58: / Line 58: @@
 ||p is typecasted to char pointer and then dereferenced. So, returned type will be char and sizeof(char) is 1
 </quiz>