C PRIMER PLUS（第六版编程练习）8.11编程练习_5题

/*修改程序清单8.4的猜数字程序，使用更智能的猜测策略。例如，程序最初猜50，询问用户是猜大了、猜小了还是猜对了。
如果猜小了，那么下一次猜测的值应是50和100中值，也就是75。如果这次猜大了，那么下一次猜测的值应是50和75的中值，等等。
使用二分查找（binarysearch）策略，如果用户没有欺骗程序，那么程序很快就会猜到正确的答案。
#include<stdio.h>
int main(void)
{
	int guess = 1;
	printf("Pick an integer from 1 to 100. I will try to guess");
	printf("it.\nRespond with a y if my guess is right and with");
	printf("\nan n if it is wrong.\n");
	printf("Uh... is your number %d?\n",guess);
	while(getchar()!='y')
		printf("Well,then,is it %d\n",++guess);
	printf("I knew I could do it!\n");
	return 0;
}
*/
#include<stdio.h>
int main(void)
{
	int guess;
	int max = 100;
	int min = 1;
	int mid = max / 2;
	char ch;
	printf("Pick an integer from 1 to 100. I will try to guess.\n");
	scanf("%d", &guess);
	printf("Respond with b(big) or s(small), respond y if my guess is right ");
	printf("Uh... is your number %d?\n", mid);
	while ((ch = getchar()) != 'y') {
		if (ch == '\n')
			continue;
		if (ch == 'b') {
			max = mid;
			mid = (max - min) / 2 + min;
			printf("Well,then,is it %d\n", mid);
			printf("guess=%d\n", guess);
		}
		else if (ch == 's') {
			min = mid;
			mid = (max - min) / 2 + min;
			printf("Well,then,is it %d\n", mid);
			printf("guess=%d\n", guess);
		}	
	}
	
	return 0;
}