My length just changed for no reason.

Here is the code:

#include<stdio.h>
#include<windows.h>

void HeapAdjust(int *a,int s,int length);
void swap(int *a,int m,int n);

int main(){
    int a[] = {99,19,2,98,103,3,9,20,78,201,88,9,23,46,77,59,67,69,75,38};

    /* 
      bug here