27.c

折半查找算法的实现

int halfsearch(int a[],int target,int number)
{
	int i=0;
	while(i<number)
	{
		if(a[i]<=target&&target<a[i+1])
		{
			return i+1;
		}
		i++;
	}
	if(target<a[0])
	{
		return 0;
	}
	if(target>=a[number-1])
	{
		return number;
	}
}
main()
{
	int a[10];
	int i;
	int number=0;
	char ch='o',con;
	int target=0;
	int find=2;
	i=0;
	while(i<10)
	{
		a[i]=0;
		i++;
	}
	i=0;
	printf("please input the numbers\n");
	while(ch!='\n')
	{
		scanf("%d",&a[i]);
		scanf("%c",&ch);
		number=i;
		i++;
	}
	printf("Do you want to search\n");
	scanf("%c",&con);
	while(con=='Y'||con=='y')
	{
		printf("please input the target number\n");
		scanf("%d",&target);
		scanf("%c",&ch);
		find=0;
		find=halfsearch(a,target,number);
		printf("%d",find);
		printf("Do you want to search\n");
		scanf("%c",&con);
	}


}