Problem in C : How to properly call function inside main - c

Question

So there is this project in Data Structures that i have to deal with this semester and it requires that i have to code in C . The problem is that i am a little bit rusty in C and i am dealing with basic problems. One of the problems is that i have to write a simple program in C that implements BubbleSort . The BubbleSort algorithm has to be a seperate function and call it in the main program . Here is my effort . The problem is that it doesnt type the sorted array . I hope you can help me .
THE CODE :
int calculateRand()
{
int num;
num = (rand())%(UPPER-LOWER+1)+LOWER;
return num;
}
void swap(int *xp, int *yp)
{
int temp=*xp;
*xp=*yp;
*yp=temp;
}
void BubbleSort(int S[], int n)
{
int up=n;
int i,j;
while(up>1)
{
j=0;
for(i=1; i<up-1; i++)
{
if(S[i]>S[i+1])
{
swap(&S[i], &S[i+1]);
j++;
}
}
}
for(i=0; i<n; i++)
{
printf("%d\n", S[i]);
}
}
int main()
{
int n,i;
printf("Parakalw dwste mia timh sto n: \n");
scanf("%d", &n);
int S[sizeof(n)];
printf("O mi taxinomimenos pinakas einai o exis \n");
for(i=0; i<n-1; i++)
{
S[i]=calculateRand();
printf("%d\n", S[i]);
}
printf("O pinakas meta thn taxinomisi einai \n");
BubbleSort(S[sizeof(n)], n);
return 0;
}

Answer 1

So if we start from the top there is a problem in the calculateRand() function as you do not declare the UPPER and LOWER variables or pass them as parameters to function.
Swap function is ok.
In the BubbleSort() function you need to decrease the up variable value after the for loop.
while(up>1)
{
for(i=1; i<up-1; i++)
{
if(S[i]>S[i+1])
{
swap(&S[i], &S[i+1]);
j++;
}
}
up--;
}
Also at this point you should start iterating from 0 instead of 1 since arrays start from index 0. So for(i=0; i<up-1; i++) is the correct way to go.
Lastly in the main() function when you're declaring the array variable S you shouldn't pass the sizeof(n) since n is an integer and size of an integer is 4. Instead you want to use n as it is int S[n];
For loop to populate the array should go up to n not n-1 if you want to fill all elements of the array. However if you change this you'll need to make the similar change in the BubbleSort() function.
And finally in the BubbleSort() function call you are passing the last element of the array which is an integer whereas function expects you to pass an array. It should look like this BubbleSort(S, n); instead.

Answer 2

sizeof(n) has nothing to do with the value of the variable n. It's the the size of the variable n, i.e. mostly 4 bytes for the modern architectures.
Modern variants of C permit variable size arrays thus
int S[n];
would have been legit. Otherwise
int *S = (int *)malloc(n*sizeof(int));
will help.
When you call BubbleSort , your argument should be S not S[sizeof(n)];