Problems with quicksort implementation, array as argument of function

Question

first, qsort.c, then main.c. THEY ARE ON DIFFERENT FILES.

void qsort(int array[], int start, int end){

    int temp_start = start, temp_end = end;
    int part = array[start];

    if(start >= end){
        return;
    }

    while(temp_end > temp_start){
        for(temp_end; array[temp_end] >= array[temp_start] && temp_end > temp_start; temp_end --);

        array[temp_start] = array[temp_end];

        for(temp_start; array[temp_start] < part && temp_end > temp_start; temp_start++);

        array[temp_end] = array[temp_start];
    }

    array[temp_start] = part;

    qsort(array, start, temp_start);
    qsort(array, temp_start, end);
}

=================================================================================

#define MAX 7
#define START_POS 0
#define END_POS (MAX - 1)

void qsort(int array[], int start, int end);
void show(int array[], int size);
void random_input(int array[], int size);

int main(){
    int array[MAX];

    random_input(array, MAX);
    show(array, MAX);
    qsort(array, START_POS, END_POS);
    show(array, MAX);

    return 0;
}

I pass the array to qsort, but apparently I'm not able to modify its contents. Using the debugger I find that whenever a variable change on the array is issued, no change is shown on the debugger.

I have no idea of what is happening, if I let it go for a while the program ends up being stopped by windows.

I'm new to arrays and recursion, please help I'm really at loss here.

Answer 1

I solved it, the call wasn't right making this kind of situation possible.

        7         8

temp_start ^

temp_end....^

and then calls were:

qsort(array, start, temp_start) //start and temp_start are equal, after call qsort returns

        7

temp_start ^

temp_end....^

//and the second call

qsort(array, temp_start, end)

        7         8

temp_start ^

end .........................^

so the second qsort call will never return, it will end on the scenario from the beginning again:

//first call

        7

temp_start ^

temp_end....^

//second call

        7         8

temp_start ^

temp_end.....................^

A change of the second qsort call to:

qsort(array, temp_start + 1, end);

solves the problem and gives correct program output.