Linux Boot process

Bootchart
Boot process visualization

Programming Puzzle

No, I didn't answer all those myself :-)

1. Write a "Hello World" program in 'C' without using a semicolon.

void main()
{
if (printf("Hello World!\n") {}
}

2. Write a C++ program without using any loop (if, for, while etc) to print numbers from 1 to 100 and 100 to 1;

void main()
{
printf("1\n2\n3\n... and so on...");
}

3. C/C++ : Exchange two numbers without using a temporary variable.

x^=y; y^=x; x^=y; #XOR!

4. C/C++ : Find if the given number is a power of 2.

if (!( x & (x-1)) printf("x is a power of 2\n");

5. C/C++ : Multiply x by 7 without using multiplication (*) operator.

x = (x6. C/C++ : Write a function in different ways that will return f(7) = 4 and f(4) = 7

int function(int x) {
switch (x)
{
case 7: return 4;
case 4: return 7;
}
}

6. C/C++ : Write a function in different ways that will return f(7) = 4 and f(4) = 7
7. Remove duplicates in array
8. Finding if there is any loop inside linked list.
9. Remove duplicates in an no key access database without using an array
10. Convert (integer) number in binary without loops.

I assume you mean to print the binary form of an int without using loops. So I didn't use a loop, I used recursion.

;) void printbits(int x) { int n=x%2; if(x>=2) printbits(x/2); printf("%d", n); }

11. Write a program whose printed output is an exact copy of the source. Needless to say, merely echoing the actual source file is not allowed.
12. From a 'pool' of numbers (four '1's, four '2's .... four '6's), each player selects a number and adds it to the total. Once a number is used, it must be removed from the pool. The winner is the person whose number makes the total equal 31 exactly.
13. Swap two numbers without using a third variable.

Same problem as #3 above.

14. Given an array (group) of numbers write all the possible sub groups of this group.