C Primer Plus(第6版)第七章复习题答案

7.11复习题

1. a. false
   b. true
   c. false

a. number >= 90 && number < 100
b. ch != 'q' && ch != 'k'
c. (number >= 1 && number <= 9) && number != 5
d. number < 1 || number > 9

3. 修改后的程序如下

#include <stdio.h>
int main(void)
{	
	int weight, height;
	
	scanf("%d %d", &weight, &height);  //修改
	if (weight < 100 && height > 64)
		if (height >= 72)
			printf("You are very tall for your weight. \n");
		else 		//修改
			printf("You are tall for your weight. \n");
	else if (weight > 300 && height < 48)	//修改
		printf(" Your are quite short for your weight. \n"); //修改
		else
			printf("Your weight is ideal. \n");

	return 0;
}

重点是，else 与 离它最近的 if 匹配， 从上向下看

4. a. 1
   b. 0
   c. 1
   d. 6
   e. 10
   f. 0
5. 下面的程序将会打印如下效果：

*#%*#%$#%*#%*#%$#%*#%*#%$#%*#%*#%
// 注意 else的范围只有后面的第一条语句printf('*');

下面的程序将会打印如下内容：

fat hat cat Oh no !
hat cat Oh no !
cat Oh no !

修改后的程序如下

#include  <stdio.h>
int main(void)
{	
	char ch;
	int lc = 0;
	int uc = 0;
	int oc = 0;
	
	while ((ch = getchar()) != '#') 
	{
		if (islower(ch))
			lc++;
		else if (isupper(ch))
			uc++;
		else
			oc++;
	}
	printf("%d lowercase, %d uppercase, %d other case", lc, uc, oc);

	return 0;
}

Your are 65, Here is your gold watch.
Your are 65, Here is your gold watch.
Your are 65, Here is your gold watch.
Your are 65, Here is your gold watch.
Your are 65, Here is your gold watch.
Your are 65, Here is your gold watch.
Your are 65, Here is your gold watch.
无限循环

q	//输入
Step 1
Step 2
Step 3	//注意 执行标签语句
c	//输入
Step 1
h	//输入
Step 1
Step 3
b	//输入
Step 1
Done

/*
重写复习题9，但是不能使用 continue 和 goto 语句
*/
#include <stdio.h>
int main(void)
{	
	char ch;

	while ((ch = getchar()) != '#')
	{
		if (ch != '\n')
		{
			printf("Step 1 \n");
			if (ch != 'c')
			{
				if (ch == 'b')
					break;
				if ( ch == 'h')			//这几句还可以这样写
					printf("Step 3 \n");	// if (ch != 'h')
				else				//    printf("Step 2 \n");
				{				// printf("Step 3 \n");
					printf("Step 2 \n");	//
					printf("Step 3 \n");	//
				}				//
			}
		}
	}
	printf("Done \n");

	return 0;
}