how to compute time complexity

[forgottendreams340]

Hello everyone!

Can someone help me out how to compute the time complexity of this codes:

#include <stdio.h>

void main()

{

    int i;

    for(i = -20; i <=-11; i++)

        printf("%d ", i);

    printf("\n");

}

#include <stdio.h>

 

void main()

{

    int i;

    for(i = 0; i <= 10; i++)

        printf("%d ", i*i);

    printf("\n");

}

and if you know some sites that has codes and it's pseudocode in c++, kindly post it pls 'coz I need sample codes, Thank you in advance...

[NGen]

What do you mean by time complexity? How long it takes to compute the code?

[Bazzy]

Why should you find the complexity of those programs?

http://en.wikipedia.org/wiki/Computational_complexity_theory

[forgottendreams340]

I need to find the time complexity of those programs because this is a project given to me, and I totally don't know how to solve it.. :-(

[johnkravetzki]

so you don't need computational complexity for your codes? (IMO its O(10) in 1st case and O(11) in the second one, correct me if I'm wrong)

i guess you need execution time of both codes?

edit

If yes, you can use clock() function from <ctime> or GetTickCount() from <windows.h>

edit2

I even found a nice example:
http://www.dreamincode.net/forums/showtopic24685.htm

[Bazzy]

From Wikipedia:

The time complexity of a problem is the number of steps that it takes to solve an instance of the problem as a function of the size of the input, using the most efficient known algorithm

Here is no input, so complexity = constant

[chrisname]

Further to johnkravetzki's mention of the clock() function; here's an example:

double start = clock() // It has the "float" datatype
SomeFunction();
double end = clock(); // Take the time again.

double duration = end - start / CLOCKS_PER_TICK;