Thread: arrays problem

looking at the program following,i don't know how the line7 is working(what's the j variable advantages?!)!!! i'm trying on arrays and know the concepts but i don't know exactly how to use them(of course in a more complex programs in which i should use more than one array and loops togather!!

Code:

main()
{
    int i,a,j,num[10];
    for(i = 0;i < 10;i++)
        scanf("%d",&num[i]);

   for(j = 0;j < 9;j++)
    for(i = 0;i < 10-j;i++)
        if(num[i] > num[i+1]){
            a = num[i];
            num[i] = num[i+1];
            num[i+1] = a;
        }
        printf("\n\n");
            for(i = 0;i < 10;i++)
                printf("%d\n",num[i]);

}

tnx.

The purpose of the 'for' loop at line 7 is to execute statements 8-13 multiple times(in this case 9 times). This is done so that we end up with a sorted array.

If you have a hard time trying to understand the algorithm, I suggest you to take a piece of paper, write down 10 numbers and see what happens to the arrangement of the numbers after each iteration.

i know that the first loop loops 9 times, but the problem is here that i think these two loops loop too much(the first loops 9 time and within it the second one loops and these are multipling to each other). i think it was enough if we had just the second one - ofcourse with "for(i=0;i<10;i++)"- that loops the same as array size!!!(unfortunatly if it would be as this,it doesn't work) the program order the numbers..

If you have only second loop, then during the completion of that loop, only first largest element will be found out and placed in the right position.
For sorting other elements we are using first for loop.
Note the second for loop. here the second loop iterates till "10-j". So when j=1, first largest element will be found out
and when j=2 second largest element will be found out and so on