Trying to understand bubblesort function

I am fairly new to C and programming in general, and I have a question about looping in the following bubble sort function:

    void sort(int values[], int n);
    {
        int c, d, t;

        for (c = 0; c < (n - 1); c++)
        {
            for (d = 0; d < c - n - 1; d++)
            {
                if (values[d] > values[d + 1])
                {
                    t = values[d];
                    values[d] = values[d + 1];
                    values[d + 1] = t;
                }
            }
        }
    }

The part that I'm specifically trying to understand is the second for loop:

    for (d = 0; d < c - n - 1; d++)

I understand that the function is iterating through the array each time, comparing side-by-side values up until the last sorted element and bubbling the biggest element to the end of the array; however, I cannot seem to wrap my head around the meaning of:

    while d < c - n - 1;

and how it translates. When I play this out in my mind I'm imagining that on the first time looping, d < c - n - 1 equates to 0 < 0 - 10 - 1. It seems to me that since c is always going to be less than n - 1, subtracting n - 1 from c will always result in a value less than 0, and d is never less than 0 so should never execute. I know that I'm just looking at this wrong and will probably have a 'duh' moment when the answer is presented, but this is bothering me.

If I put the first for loop into words, it says: while c is less than the length of the array, execute the contents of this loop then increment c. Can someone put the second for loop into words in a similar way, explaining the meaning of d < c - n - 1?

Solution

Try this code instead.

#include<stdio.h>

void sort(int values[], int n)
{
int c,d,t=n;
//if we have n elements then outer loop must iterate for n times.
for(c=0;c<n;c++)
{
    /*after every complete iteration we get a
    sorted element in last position, next iteration
     will be one less, so we assigned value of n into t
     and we will decrease it by 1 after every internal complete iteration.
     */
     for(d=0;d<t-1;d++)
        {
          if(values[d]>values[d+1])
            {
               int temp;
               temp = values[d+1];
               values[d+1] = values[d];
               values[d] = temp;
            }
        }
    //decrease the test cases in next iteration,
    //we already have last element sorted.
    t--;
  }
}
int main()
{
  int i;
  int values[]={24,12,2,4,6};
  sort(values, 5);

   for(i=0; i<5; i++)
     {
        printf("%d\n",values[i]);
     }

return 0;
}

Make Changes according to your need.