WeiBing

1．读入或用随机函数生成10个整数作为数组元素； 

2．调用排序函数进行排序，输出升序的排序结果； 

3．修改排序函数，变成降序排序，调用之后输出排序结果； 

4．读入一个数组元素，调用折半查找函数，输出该元素在数组中的位置； 

5．读入一个非数组元素，调用折半函数，输出“找不到” ； 

6．改进折半查找函数，使之能统计元素之间的比较次数并输出。

#include "stdio.h"
#include "time.h"
void shell_insert(char *L,int dk,int type) {
int i,j;
    for(i=dk+1;i<=10;i++) {
        if( (type ? L[i]L[i-dk]) ) {
            L[0]=L[i];
            for(j=i-dk;j>0&&(type?L[0]L[j]);j-=dk)
                L[j+dk]=L[j];
            L[j+dk]=L[0];
        }
    }
}
void shell_sort(char *L,int type) {
int i,j,dlta[3]={3,2,1};
    for(i=0;i<3;i++) {
        shell_insert(L,dlta[i],type);
/*    printf("the %d time sorted_group is ",i);
    for(j=0;j<11;j++)
        printf("%c ",L[j]);
    printf("\n");
*/    }
}
int bin_search(char *L,char key,int *count) {
int low,high,mid;
low=1;high=10;
*count=1;
while(low <= high) {
        mid=(low+high)/2;
        if(L[mid]==key) return mid;
        else if(L[mid]>key) low = mid+1;
        else high = mid -1;
        (*count)++;
        }
return 0;
}
int main(void)
{
int i,find_count;
char key,group[11];
    srand((unsigned)time(NULL));
    printf("the group is ");
    for(i=1;i<11;i++)
        printf("%c ",group[i]=rand()%26+'A');
    printf("\n");
    shell_sort(group,1);
    printf("the up sorted_group is ");
    for(i=1;i<11;i++)
        printf("%c ",group[i]);
    printf("\n");
    shell_sort(group,0);
    printf("the down sorted_group is ");
    for(i=1;i<11;i++)
        printf("%c ",group[i]);
    printf("\n");
    printf("enter the key you want\n");
    scanf("%c",&key);
  while(1){
    if(i=bin_search(group,key,&find_count))
        printf("position is %d,find_count is %d\n",i,find_count);
    else
        printf("not found\n");
    printf("continue? n for exit\n");
    scanf(" %c",&key);
    if(key=='n')break;
  }
}