[dudaefj]

6 loops
all make the same thing
all make 100milion iterations
but they spend VERY different times

PHP код:

    new a = GetTickCount();
    new n = 0;
    
    
    a = GetTickCount();
    while( n < 1000000000 )
        if(n++ == 100000000)
            break;
    printf("tempo1 = %d",GetTickCount() - a);
    n = 0;
    a = GetTickCount();
    while( n < 200000000 )
        if(n++ == 100000000)
            break;
    printf("tempo2 = %d",GetTickCount() - a);
    
    n = 0;
    a = GetTickCount();
    while( n < 100000001 )
        if(n++ == 100000000)
            break;
    printf("tempo3 = %d",GetTickCount() - a);
    
    n = 0;
    a = GetTickCount();
    while( 1 < 2 )
        if(n++ == 100000000)
            break;
    printf("tempo4 = %d",GetTickCount() - a);
    
    n = 0;
    a = GetTickCount();
    for(new t = 0; t < 100000000; t++)
        if(n++ == 100000000)
            break;
    printf("tempo5 = %d",GetTickCount() - a);
    
    n = 0;
    a = GetTickCount();
    for(new t = 0; t < 10000002; t++)
        if(n++ == 100000000)
            break;
    printf("tempo6 = %d",GetTickCount() - a); 


result:

Quote:

[23:41:30] tempo1 = 3705 [23:41:33] tempo2 = 3745 [23:41:37] tempo3 = 3733 [23:41:39] tempo4 = 1625 [23:41:41] tempo5 = 2698 [23:41:42] tempo6 = 268

now I ask:
why?

[Babul]

Код:

[23:41:42] tempo6 = 268

is because the loop is stopping @ 10,000,000, all others are stopping @ 100,000,000. so the real value is more like 2680.

Код:

[23:41:39] tempo4 = 1625

is faster due to a missing insruction (math operator) using the "while( 1 < 2 )". the constant expressions are being precompiled, since the 1 and 2 are constants.

[iggy1]

I suppose number 4 is fastest because it uses constant values in the expression rather than variables. 1 will always be less than 2, so it wont have to check the value each iteration. (i guess)

EDIT: Didn't know this was already mentioned above.