quick sort mine optimised

#include<stdlib.h>
#include<conio.h>
#include<stdio.h>

void swap(int *p,int *q)
{
    int temp=*p;
    *p=*q;
    *q=temp;
}

void printarray(int a[],int n)
 {
    int i;
    for (i=0;i<n;i++)
         printf("%d, ",a[i]);
 }

int partition(int a[],int l,int h,char ch)
{
    int pivot,i,j;
    pivot=a[l];
    i=l;j=h;
    while(i<j)
    {
        if(ch=='2'){
        do
        {
            i++;
        }while(a[i]>=pivot);

        do
        {
            j--;
        }while(a[j]<pivot);
        if(i<j)
        swap(&a[i],&a[j]);
        }
        else if(ch=='1')
        {
            do
        {
            i++;
        }while(a[i]<=pivot);

        do
        {
            j--;
        }while(a[j]>pivot);
        if(i<j)
        swap(&a[i],&a[j]);
        }

        }
        swap(&a[l],&a[j]);
        return j;


}

void quick_sort(int a[],int i,int j,int ch)
{
    int loc;
    if(i<j)
    {
        loc=partition(a,i,j,ch);
        quick_sort(a,i,loc,ch);
        quick_sort(a,loc+1,j,ch);
    }
}

main()
{
    int a[20],n,i;
    char ch;
    printf("enter the size of array : ");
    scanf("%d",&n);
    for(i=0;i<n;i++)
    {
        printf("enter the data : ");
        scanf("%d",&a[i]);
    }
    while(1)
    {
    printf("\n1>sort ascending\n2> sort descending\n3> exit\nenter your choice : ");
    fflush(stdin);
    ch=getche();
    if(ch=='1')
    printf("the array sorted in ascending order is : ");
    else if(ch=='2')
    printf("the array sorted in descending order is : ");
    else{exit(0);}
    quick_sort(a,0,n,ch);
    printarray(a,n);
    }
}