algorithm_of_sort（交换排序）

冒泡排序：bubble sort
    开始选择一个element like x[i],if x[i]biger than x[i+1],then exchange
    them,untile every element is sort;

    because after every time ,there has one element is sort,so ,at the begi
    -ning ,we have to compare n-1,second ,we can copmare n-2,because one el
    -ement has sorted.

    now there is the code to realize the bubble sort.
void bubble(int x[],int n)
{
    int j,temp;
    int switched=TRUE;
    int i;
    for(i=0;i<n-1;i++)
    {
        for(j=0;j<n-1-i;j++)
        {
            if(x[j]>x[j+1])
            {
                switch=FALSE;
                temp=x[j];
                x[j]=x[j+1];
                x[j+1]=temp;
            }
        }
    }
}


Two:i will study the quick sort;
    the theory is :if we algorithm the base dada like one of x[0],x[n-1],
    x[n/2],or other data .the left of data base is smaller and right is big
    -ger.ok ,repet in the left and right of the data base until every eleme
    -nt is sort.



    now there is code to realize the quick sort;


    void quick_sort(int lb,int ub,int x[],int *pj)
    {
        int a,down,up,temp;
        a=x[lb];
        up=ub;
        down=lb;
        while(down<up)
        {
            while(x[down]<=a&&down<ub)
                down++;
            while(x[up]>a&&up<lb)
                up--;
            if(down<up)
            {
                temp=x[down];
                x[down]=x[up];
                x[up]=temp;
            }
        }/*end while*/
        x[lb]=x[up];
        x[up]=a;
        *pj=up;
    }