#include <stdio.h>

char get_choice(void);

char get_first(void);

int get_int(void);

void count(void);

int main(){

	int choice;

	void count (void);

	while ((choice =get_choice())!='q')

	{

		switch(choice)

		{

		   case 'a' : printf("Buy low ,shell high \n");

			break;

			case 'b' : putchar('\a');

			break;

			case 'c' : count();

			break;

			default : printf("Buy adbcxz \n");

			break;

		}

	}

	printf("Bye .\n" );

	return 0;

}

void count (void)

{

	int n ,i;

	printf("Count how far ? Enter an integer : \n");

	n=get_int();

	for(i=1; i<=n;i++)

	{

		printf("%d\n",i);

	}

	while (getchar() !='\n')

		continue;

}

char get_choice(void)

{

	char ch;

	printf("Enter the letter of your choice :\n");

	printf(" a. advice        b. bell\n");

	printf("c. count          d.quit\n");

	ch=get_first();

	while((ch<'a'||ch>'c') && ch!='q')

	{

		printf("please respond with a,b,c,or q\n");

		ch=get_first();

	}

	return ch;

}

//获取输入字符串

char get_first(void)

{

	char ch;

	ch=getchar();

	while(getchar() !='\n')

	continue;

	return ch;

}

int get_int(void)

{

	int input;

	char ch;

	while(scanf("%d",&input) !=1)

	{

		while((ch= getchar()) !='\n')

			putchar(ch);

		printf(" is not an integer .\n please enter an ");

		printf("integer value ,such as 25, -178, or 3:");

	}

	return input;

}