前言：这章是昨日刚打完的，其实第五题不是很满意，我也有点搞的一头雾水，当然其他章肯定有点小细节问题我还没发现，突然想起作者写到的有句话“不管你的程序提示打完多好，总会有人吐槽这个程序有多烂”，前几个我输入验证做的不是很完美（其实是当时有点烦就懒得做了），如被小伙伴学习参考，My pleasure.

仅供参考，新手勿喷。

CH08 Code answer 1:

#include <stdio.h>
#include <string.h>
int main(void)
{
	char ch;
	int count = 0;
	while((ch = getchar()) != EOF)			//这里会把换行符也读取 
		count++;
	printf("%d",count);
 } 

CH08 Code answer 2:

#include <stdio.h>
int main()
{
	char ch;
	int count = 0;
	while((ch = getchar()) != EOF)			//有个问题就是一换行就触发了 
	{
		count++;
		if(ch < ' ')
		{
			if(ch == '\t')
				printf("\\t-%d ",ch);
			else if(ch == '\n')
				printf("\\n-%d ",ch);
			else
				printf("^%c-%d ",ch+64,ch);
		}
		else
			printf("%c-%d ",ch,ch);
		count%10 == 0  ? count=0,printf("\n") : count ;
	 } 
 } 

CH08 Code answer 3:

#include <stdio.h>
#include <ctype.h>
int main(void)
{
	char ch;
	int lower_count=0,upper_count=0;
	while((ch = getchar()) != EOF)
	{
		if(islower(ch))
			lower_count++;
		else if(isupper(ch))
			upper_count++;
	}
	printf("upper:%d lower:%d",lower_count,upper_count);
}

CH08 Code answer 4:

#include <stdio.h>
#include <ctype.h>
int main(void)
{
	int later_count,word_count,flag;
	char ch;
	later_count=word_count=flag=0;
	while((ch = getchar()) != EOF)
	{
		if((isupper(ch) || islower(ch)) && !ispunct(ch))
		{
			later_count++;
			flag = 1;
		}
		else if(isspace(ch) && flag == 1)
		{
			word_count++;
			flag = 0;
		}
	}
	printf("later:%d word:%d avg:%f",later_count,word_count,(float)later_count/(float)word_count);
}

CH08 Code answer 5:

#include <stdio.h>
int main(void)
{
	int low=0,high=100;
    int guess = (high+low)/2;
    char ch;
    
    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 ((ch = getchar()) != 'y')      /* get response, compare to y */
    {
    	if(ch == 'h')
    	{
    		low = 0;
    		high = guess;
    		guess = (low+high)/2;
    		printf("Well, then, is it %d?\n", guess);
		}
    	else if(ch == 'l')
    	{
    		low = guess;
    		high = 100;
    		guess = (low+high)/2;
    		printf("Well, then, is it %d?\n", guess);
		}
		while(getchar() != '\n')
			continue;
	}    
    printf("I knew I could do it!\n");
    
    return 0;
}

CH08 Code answer 6:

#include <stdio.h>
#include <ctype.h>
int main(void)
{
	char ch;
	while( isspace(ch = getchar()) )		//获取第一个非空字符 
		continue;
		
	putchar(ch);							//输出第一个字符	
	
	while(getchar() != '\n')				//将多余的缓冲区输入排除 
		continue;
}

CH08 Code answer 7:

这个是修改之前的程序，所以有些宏定义还留着。

#include <stdio.h>
#include <ctype.h>

#define SALARY 10
#define OVERTIME 40
#define Q300 0.15
#define X150 0.2
#define OM 0.25

#define r1 8.75
#define r2 9.33
#define r3 10.00
#define r4 11.20

void Print(void); 
char get_choice(void);
char get_first(void);

int main(void)
{
	
	float money;
	int ho;	
	
	char choice;
	float sa; 
	
	while((choice = get_choice()) != 'q')
	{
			switch (choice)
			{
				case 'a':
					sa = r1;
					break;
				case 'b':
					sa = r2;
					break;
				case 'c':
					sa = r3;
					break;
				case 'd':
					sa = r4;
					break;
			}
			
			printf("请输入你工作了多少小时:");
			scanf("%d",&ho);
			if(ho > 40)
				money = (ho-40)*1.5*sa + 40*sa;
			else
				money = ho*sa;

			if(money <= 300)
				money = money - Q300 * money;
			else if(money <= 450)
				money = money - ((money-300)*X150 + 300 * Q300);
			else
				money = money - ((money-450)*OM + 150*X150 + 300*Q300);
			printf("你的工资为%f\n",money);	
	}
	printf("bye!");
 } 
 
 void Print(void)
 {
 	printf("*****************************************************************\n");
	printf("Enter the number corresponding to the desired pay rate or action:\n");
	printf("a) $8.75/hr                          b) $9.33/hr\n");
	printf("c) $10.00/h                          d) $11.20/hr\n");
	printf("q) quit\n");
	printf("*****************************************************************\n");
	printf("请选择:");
  } 
  
  char get_first(void)
  {
  	char ch;
  	
	while( isspace(ch = getchar()) )		//获取第一个非空字符 
		continue;
		
	//putchar(ch);							//输出第一个字符	
	
	while(getchar() != '\n')				//将多余的缓冲区输入排除 
		continue;
		
	return ch;
  }
  
  char get_choice(void)
  {
  	char ch;

  	Print();
  	ch = get_first();
  	while( (ch < 'a' || ch > 'd') && ch != 'q' )
  	{
  		printf("please respond with a, b, c, d, or q!");
  		ch = get_first();
	}
  	return ch;	
  }

CH08 Code answer 8:

#include <stdio.h>
#include <ctype.h>

char get_choice(void);
char get_first(void);
float get_float(char choice);

int main(void)
{
	float a,b;
	char choice;
	
	while( (choice = get_choice()) != 'q')
	{
		printf("Enter first number:"); 
		a = get_float(choice);
		printf("Enter second number:");
		b = get_float(choice);
		switch(choice)
		{
			case 'a':
				printf("%f + %f = %f\n",a,b,a+b);
				break;
			case 's':
				printf("%f - %f = %f\n",a,b,a-b);
				break;
			case 'm':
				printf("%f * %f = %f\n",a,b,a*b);
				break;
			case 'd':
				printf("%f / %f = %f\n",a,b,a/b); 
				break;
			default:
				printf("program error!\n");	
		}
	}
	printf("bye!");	
	
	return 0;
} 

char get_choice(void)
{
	char ch;
	
	printf("**********************************\n");
	printf("Enter the operation of your choice\n");
	printf("a. add           s. subtract\n");
	printf("m. multiply      d. divide\n");
	printf("q. quit\n");
	printf("**********************************\n");
	
	ch = get_first();
	while( ch != 'a' && ch != 's' && ch != 'm' && ch != 'd' && ch != 'q')
	{
		printf("please respond a, s, m, d or q\n");
		ch = get_first();	
	} 
	return ch;
}

char get_first(void)
{
	char ch;
	
	while( isspace(ch = getchar()) )		//选到第一个非空字符 
		continue;
	while(getchar() != '\n')				//去掉多余字符				
		continue;
	return ch;	
} 

float get_float(char choice)
{
	float input;
	char ch;
	
	while(scanf("%f",&input) != 1)
	{
		while((ch = getchar()) != '\n')
			putchar(ch);
		printf(" is not an num.\nplease enter an num value,such as 2, -178 or 3.5:"); 
	}
	
	if(choice == 'd' && input == 0 )
	{
		printf("Enter a number other than 0:");
		input = get_float(choice);					//重新调用这个函数,当里面返回了正确的值要记得接受再向上返回 
	} 
	return input;
}