Write an efficient C program to count the number of bits set in an
unsigned integer.
i/p     o/p
====    ===
0(00)    0
1(01)    1
2(10)    1
3(11)    2
.....  ...

Write a small C program, which while compiling takes another program
from input terminal, and on running gives the result for the second
program. (NOTE: The key is, think UNIX).


Suppose, the program is 1.c
Then, while compiling
$ cc -o 1 1.c
int main()
{
    printf("Hello World\n");
}
^D
$ ./1
Hello World
$

Given a string s1 and a string s2, write  a snippet to say whether s2 is a
rotation of s1 using only one call to strstr routine?

(eg given s1 = ABCD and s2 = CDAB, return  true,
      given s1 = ABCD, and s2 = ACBD , return false)

What's the  "condition" so that the following code
snippet  prints both HelloWorld !

if  "condition"
        printf ("Hello");
else
        printf("World");