//7.1
#include<stdio.h>
int main(void)
{
const int FREEZING = 0;
float temperature;
int cold_days = 0;
int all_days = 0;
printf("Enter the list of daily low temperature.\n");
printf("Use Celsius, and enter q to quit.\n");
while (scanf("%f",&temperature) == 1)
{
all_days++;
if (temperature < FREEZING)
cold_days++;
}
if (all_days != 0)
printf("%d days total: %.1f%% were below freezing.\n",
all_days, 100.0 * (float) cold_days / all_days);
if (all_days == 0)
printf("No data entered!\n");
return 0;
}
/* 7.2 */
#include<stdio.h>
#define SPACE ' '
int main(void)
{
char ch;
ch = getchar(); //讀取一個字符
while (ch != '\n') //當一行未結束
{
if (ch == SPACE) //留下空格
putchar(ch); //該字符不變
else
putchar(ch + 1);//改變其他字符
ch = getchar(); //獲取下一個字符
}
putchar(ch); //打印換行符
return 0;
}
/* 7.3 */
#include<stdio.h>
int main(void)
{
char ch;
while ((ch = getchar()) != '\n')
{
if (isalpha(ch)) //如果是一個字符
putchar(ch + 1);
else
putchar(ch);
}
putchar(ch);
return 0;
}
/* 7.4 */
#include<stdio.h>
#define RATE1 0.13230
#define RATE2 0.15040
#define RATE3 0.30025
#define RATE4 0.34025
#define BREAK1 360.0
#define BREAK2 468.0
#define BREAK3 720.0
#define BASE1 (RATE1 * BREAK1)
#define BASE2 (BASE1 + (RATE2 * (BREAK2 - BREAK1)))
#define BASE3 (BASE1 + BASE2 + (RATE3 * (BREAK3 - BREAK2)))
int main(void)
{
double kwh;
double bill;
printf("Please enter the kwh used.\n");
scanf("%lf",&kwh);
if (kwh <= BREAK1)
bill = RATE1 * kwh;
else if (kwh <= BREAK2)
bill = BASE1 + (RATE2 * (kwh - BREAK1));
else if (kwh <= BREAK3)
bill = BASE2 + (RATE3 * (kwh - BREAK2));
else
bill = BASE3 + (RATE4 * (kwh - BREAK3));
printf("The charge for %.1f kwh is $%1.2f.\n",kwh, bill);
return 0;
}
/* 7.5 */
#include<stdio.h>
#include<stdbool.h>
int main(void)
{
unsigned long num;
unsigned long div;
bool isPrime;
printf("Please enter an integer for analysis: ");
printf("Enter q to quit.\n");
while (scanf("%lu",&num) == 1)
{
for (div = 2,isPrime = true; (div * div) <= num;div++)
{
if (num % div == 0)
{
if(div * div != num)
printf("%lu is divisible by %lu and %lu.\n",
num, div, num / div);
else
printf("%lu is divisible by %lu.\n",
num, div);
isPrime = false;
}
}
if (isPrime)
printf("%lu is prime.\n",num);
printf("Please enter another integer for analysis: ");
printf("Enter q to quit.\n");
}
printf("Bye.\n");
return 0;
}
/* 7.6 */
#include<stdio.h>
#define PERIOD '.'
int main(void)
{
char ch;
int charcount = 0;
while ((ch = getchar()) != PERIOD)
{
if (ch != '"' && ch != '\'')
charcount++;
}
printf("There are %d non-quote characters.\n",charcount);
return 0;
}
/* 7.7 */
#include<stdio.h>
#include<ctype.h>
#include<stdbool.h>
#define STOP '|'
int main(void)
{
char c;
char prev;
long n_chars = 0L;
int n_lines = 0;
int n_words = 0;
int p_lines = 0;
bool inword = false;
printf("Enter text to be analyzed (| to derminate):\n");
prev = '\n';
while ((c = getchar()) != STOP)
{
n_chars++;
if (c == '\n')
n_lines++;
if (!isspace(c) && !inword)
{
inword = true;
n_words++;
}
if (isspace(c) && inword)
inword = false;
prev = c;
}
if (prev != '\n')
p_lines = 1;
printf("characters = %ld, words = %d, lines = %d, ",
n_chars, n_words, n_lines);
printf("partial lines = %d\n",p_lines);
return 0;
}
/* 7.8 */
#include<stdio.h>
#define COVERAGE 350
int main(void)
{
int sq_feet;
int cans;
printf("Enter number of square feet to be painted:\n");
while (scanf("%d",&sq_feet) == 1)
{
cans = sq_feet / COVERAGE;
cans += ((sq_feet % COVERAGE == 0)) ? 0: 1;
printf("You need %d %s of paint.\n",cans,
cans == 1 ? "can" : "cans");
printf("Enter next value (q to quit):\n");
}
return 0;
}
/* 7.9 */
#include<stdio.h>
int main(void)
{
const float MIN = 0.0f;
const float MAX = 100.0f;
float score;
float total = 0.0f;
int n = 0;
float min = MAX;
float max = MIN;
printf("Enter the first score (q to quit):");
while (scanf("%f",&score) == 1)
{
if (score < MIN || score > MAX)
{
printf("%0.1f is an invalid value. Try again: ",score);
continue;
}
printf("Accepting %0.1f:\n",score);
min = (score < min) ? score : min;
max = (score > max) ? score : max;
total += score;
n++;
printf("Enter next score (q to quit): ");
}
if (n > 0)
{
printf("Average of %d scores is %0.1f.\n", n, total/n);
printf("Low = %0.1f, high = %0.1f\n", min, max);
}
else
printf("No valid scores were entered.\n");
return 0;
}
/* 7.10 */
#include<stdio.h>
int main(void)
{
float length, width;
printf("Enter the length of the rectangle:\n");
while (scanf("%f",&length) == 1)
{
printf("Length = %0.2f:\n",length);
printf("Enter its width:\n");
if (scanf("%f",&width) != 1)
break;
printf("Width = %0.2f:\n",width);
printf("Area = %0.2f:\n",length * width);
printf("Enter the length of the rectangle:\n");
}
printf("Done.\n");
return 0;
}
/* 7.11 */
#include<stdio.h>
#include<ctype.h>
int main(void)
{
char ch;
printf("Give me a letter of the alphabet, and i will give ");
printf("an animal name\nbeginning with that letter.\n");
printf("Please type in a letter; type # to end my act.\n");
while ((ch = getchar()) != '#')
{
if ('\n' == ch)
continue;
if (islower(ch))
switch (ch)
{
case 'a':
printf("argali, a wild sheep of Asia\n");
break;
case 'b':
printf("babirusa, a wild pig of Malay\n");
case 'c':
printf("coati, racoonlike mammal\n");
break;
case 'd':
printf("desman, aquatic, molelike critter\n");
break;
case 'e':
printf("echidna, the spiny anteater\n");
break;
case 'f':
printf("fisher, brownish marten\n");
break;
default:
printf("That's a stumper!\n");
}
else
printf("I recognize only lowercase letters.\n");
while (getchar() != '\n')
continue; //跳過輸入行的剩餘部分
printf("Please type another letter or a #.\n");
}
printf("Bye!\n");
return 0;
}
/* 7.12 */
#include<stdio.h>
int main(void)
{
char ch;
int a_ct, e_ct, i_ct, o_ct, u_ct;
a_ct = e_ct = i_ct = o_ct = u_ct = 0;
printf("Enter some text; enter # to quit.\n");
while ((ch = getchar()) != '#')
{
switch (ch)
{
case 'a':
case 'A': a_ct++;
break;
case 'e':
case 'E': e_ct++;
break;
case 'i':
case 'I': i_ct++;
break;
case 'o':
case 'O': o_ct++;
break;
case 'u':
case 'U': u_ct++;
break;
default : break;
}
}
printf("number of vowels: A E I O U\n");
printf(" %4d %4d %4d %4d %4d\n",
a_ct, e_ct, i_ct, o_ct, u_ct);
return 0;
}