15.what is the disadvantage of using macros?
16.what is the self-referential structure?
17.can a union be self-referenced?
18.What is a pointer?
19.What is the Lvalue and Rvalue?
20.what is the difference between these initializations?
21.Char a[]=”string”;
22.Char *p=”literal”;
23.Does *p++ increment p, or what it points to?
Answers were Sorted based on User's Feedback
Answer / abdur rab
The difference between
21...in char a[]="string";
22... in char *p="literal";
is
in char a[]="string";, the memory is allocated, so the
value can be changed, it can be incremented, etc.
where as in char *p="literal";, you can just read it, may
be you can increment the pointer to point to the next
location, the content cannot be changed since this is a
string literal or BSS (Block Started by Symbol). This is
often called "const_data" or "data_const", or "literal".
23. *p++ it gets the content, and then increments the
pointer to the next location.
eg:
char a[] = {"string"};
char x;
char* p = (char*) a;
x = *p++;
printf ( "%c\n, %s\n", x, p );
output
======
s
tring
| Is This Answer Correct ? | 2 Yes | 0 No |
Answer / vignesh1988i
15)
the disadvantage is... th macros will blindly substitute the
values which we have defined......
#define sr(s) s+s
main()
{
....
...
int c;
c=sr(10)/5;
}
can u guess what will be the output..... 12... but i want
4.... the macros wil get substitute like this before
compailation
c=s+s/5;
since '/' symbol gets the first prirority... thatr wil
happen first.... but we dont wann this.... so this is an
idiotic mode of substitution............. this is its dis
advantages.......
16...
this structure pointer which points to the same structure
whrer its declared is called self referencial structure
18...
pointer are secondary constants and are derived data types
whic can hold only the address of particular data type .. as
same as the pointer is declared..
int *p;
thid m eans that it can hold hold only the address of an
integer and points to that memory location.........
19...
Lvalue is called left assignment value..... Rvalue right
assignment value;;;
if you give: x+y=m; in C statement ... it will
show these types of errors
21...in char a[]="string";
hrer we are initilizing the array of characters to an
array called a..... and implicitely it will add '\0' at last...
22... in char *p="literal";
here p is an character pointer which can hold the
address of an character type of values....
hrer p hold the address of 'l'... this is called as base
address of the array..... when we maniplate the p value (ie)
when we do pointer arithmetic we can print and those the
full string...
23...
*p++
here * has the first precedence compared to ++ operator
therefore.. the pointer p , where it is pointing at present
that value will be incremented.......
for eg:
char q[]="sorry";
char *p;
p=&q[0];
*p++;
printf("%c",p);
now the pointer points to the very first
character of q[].. when we give *p++, *p will be 's' then
while getting incremented it will increment the ascii value
.... so the OUTPUT will be 't'...........
thank you
| Is This Answer Correct ? | 3 Yes | 4 No |
void main() {int a[5],i,b=16; for(i=0;i<5;i++) a[i]=2*i; f(a,5,b); for(i=0;i<5;i++) printf("\n %d",a[i]); printf("\n %d",b); } f(int *x,int n,int y) { int i; for(i=0;i<n;i++) *(x+i)+=2; y=y+2; }wat r the errors in the prg.and improvise the prg to get o/p.?
write a programme to enter some number and find which number is maximum and which number is minimum from enterd numbers.
Can a file other than a .h file be included with #include?
what is the purpose of the code, and is there any problem with the code? int f( int n, int l, int r ) { return (n << l) >> r; }
1 1 1 1 2 1 1 3 3 1 1 4 6 4 1
How does the assert() function work?
where do we use structure pointer?
Write a program to remove the C comments(/* */) and C++ comments(//) from a file. The file should be declared in command line.
a character variable can at a time store a) 1 character b) 8 characters c) 254 characters d) none of the above
Write a program for the following series? 1 121 12321 1234321 123454321 12345654321 1234567654321 123456787654321 12345678987654321 1234567890987654321 123456789010987654321 12345678901210987654321 1234567890123210987654321 .........1234321............ ..........123454321............ ..........12345654321............ 7 8 9 0 1 Pls............?
You have an array of n integers, randomly ordered with value 1 to n-1.The array is such that there is only one and one value occurred twice. How will you find this number?
Diff between for loop and while loop?