121) void main()
{
if(~0 == (unsigned int)-1)
printf("You can answer this if you know how values are represented
in memory");
}
Answer
You can answer this if you know how values are represented
in memory
Explanation
~ (tilde operator or bit-wise negation operator) operates on
0 to produce all ones to fill the space for an integer. –1 is
represented in unsigned value as all 1's and so both are
equal.
122) int swap(int *a,int *b)
{
*a=*a+*b;*b=*a-*b;*a=*a-*b;
}
main()
{
int x=10,y=20;
swap(&x,&y);
arr2D
arr2D[1]
arr2D[2]
arr2D[3]
printf("x= %d y = %d\n",x,y);
}
Answer
x = 20 y = 10
Explanation
This is one way of swapping two values. Simple checking will help
understand this.
123) main()
{
char *p = "ayqm";
printf("%c",++*(p++));
}
Answer:
b
124) main()
{
int i=5;
printf("%d",++i++);
}
Answer:
Compiler error: Lvalue required in function main
Explanation:
++i yields an rvalue. For postfix ++ to operate an lvalue is
required.
125) main()
{
char *p = "ayqm";
char c;
c = ++*p++;
printf("%c",c);
}
Answer:
b
Explanation:
There is no difference between the expression ++*(p++)
and ++*p++. Parenthesis just works as a visual clue for the
reader to see which expression is first evaluated.
126) int aaa() {printf("Hi");}
int bbb(){printf("hello");}
iny ccc(){printf("bye");}
main()
{
int ( * ptr[3]) ();
ptr[0] = aaa;
ptr[1] = bbb;
ptr[2] =ccc;
ptr[2]();
}
Answer:
bye
Explanation:
int (* ptr[3])() says that ptr is an array of pointers to functions
that takes no arguments and returns the type int. By the
assignment ptr[0] = aaa; it means that the first function pointer in
the array is initialized with the address of the function aaa.
Similarly, the other two array elements also get initialized with the
addresses of the functions bbb and ccc. Since ptr[2] contains the
address of the function ccc, the call to the function ptr[2]() is same
as calling ccc(). So it results in printing "bye".
127) main()
{
int i=5;
printf("%d",i=++i ==6);
}
Answer:
1
Explanation:
The expression can be treated as i = (++i==6), because == is of
higher precedence than = operator. In the inner expression, ++i is
equal to 6 yielding true(1). Hence the result.
128) main()
{
char p[ ]="%d\n";
p[1] = 'c';
printf(p,65);
}
Answer:
A
Explanation:
Due to the assignment p[1] = 'c' the string becomes, "%c\n".
Since this string becomes the format string for printf and ASCII
value of 65 is 'A', the same gets printed.
129) void ( * abc( int, void ( *def) () ) ) ();
Answer::
abc is a ptr to a function which takes 2 parameters .(a). an
integer variable.(b). a ptrto a funtion which returns void. the
return type of the function is void.
Explanation:
Apply the clock-wise rule to find the result.
130) main()
{
while (strcmp("some","some\0"))
printf("Strings are not equal\n");
}
Answer:
No output
Explanation:
Ending the string constant with \0 explicitly makes no difference.
So "some" and "some\0" are equivalent. So, strcmp returns 0
(false) hence breaking out of the while loop.
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