quick sort去除无用判断

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

//int a[]={1000,10000,9,10,30,20,50,23,90,100,10};
int a[]={10,9,8,7,6,5};

int length=sizeof(a)/sizeof(int);

int swap(int start, int stop){
    int temp;
    temp=a[start];
    a[start]=a[stop];
    a[stop]=temp;
    return 0;    
}

int  quicksort(int start, int stop) {
    
    int i;    

    int ostart=start;
    int ostop=stop;

    int k=a[start];
    int middle;
    if(start >= stop){
        return 0;
    }
    
    while( start < stop ){
    
        //printf("\n begin start=%d,stop=%d ,k=%d , ostart=%d,ostop=%d\n" , start, stop, k,ostart,ostop);while((a[stop] >= k) &&(start<stop)){
            stop--;
        }

        while( (a[start] < k)  &&(start<stop)){
            start++;
        }
        //printf("after move start=%d,stop=%d ,k=%d , ostart=%d,ostop=%d\n" , start, stop, k,ostart,ostop);
        if( start < stop ){
            swap(start,stop);
        }
        //printf("may after swap start=%d,stop=%d ,k=%d , ostart=%d,ostop=%d\n" , start, stop, k,ostart,ostop);
    
    }
    quicksort(ostart, start);
    quicksort(start+1, ostop);
    
}

int main(){
    
    printf("length= %d\n",length);    
    int i;
    printf("\n");
    quicksort(0,length-1);
    printf("\n\n\n");
    for(i=0;i<length;i++){
        printf("%d\n" , a[i]);
    }
    printf("\n");
    
    return 0;
}