//本博主所写的代码仅为阅读者提供参考；
//若有不足之处请提出，博主会尽其所能修改；
//附上课后编程练习题目；
//若是对您有用的话请点赞或分享提供给它人；
//7.12 - 1.c
#include <stdio.h>
#define STOP '#'
int main(void)
{
int ch, space, enter, others;
space = enter = others = 0;
printf("Please enter some characters ('#' to quit):\n");
while ((ch = getchar()) != STOP)
{
if (ch == ' ')
{
space++;
}
else if (ch == '\n')
{
enter++;
}
else
{
others++;
}
}
printf("Here are the messages\n");
printf("Space: %d\n", space);
printf("Linefeed: %d\n", enter);
printf("Others: %d\n", others);
return 0;
}
//-------------
//7.12 - 2.c
#include <stdio.h>
#define STOP '#'
int main(void)
{
int ch;
int i = 0;
printf("Enter some characters('#' to quit):\n");
while ((ch = getchar()) != STOP)
{
if (i++ % 8 == 0)
{
putchar('\n');
}
if (ch == '\n')
{
printf("'\\n'-%3d ", ch);
}
else if (ch == '\t')
{
printf("'\\t'-%3d ", ch);
}
else
{
printf("'%c'-%3d ", ch, ch);
}
}
printf("Done.\n");
return 0;
}
//-------------
//7.12 - 3.c
#include <stdio.h>
int main(void)
{
int n, odd, even;
int e_sum, o_sum;
odd = even = 0;
e_sum = o_sum = 0;
printf("Please enter a integer (0 to quit): ");
while (scanf("%d", &n) == 1 && (n != 0))
{
if (n % 2 == 0)
{
even++;
e_sum += n;
}
else
{
odd++;
o_sum += n;
}
printf("You can enter again (0 to quit): ");
}
printf("Even number: %d\n", even);
if (even > 0)
{
printf("The average of even: %g\n", (float)e_sum / even);
}
printf("Odd number: %d\n", odd);
if (odd > 0)
{
printf("The average of odd: %g\n", (float)o_sum / odd);
}
printf("Done.\n");
return 0;
}
//-------------
//7.12 - 4.c
#include <stdio.h>
#define STOP '#'
int main(void)
{
int ch;
int n = 0;
printf("Enter some characters('#' to quit):\n");
while ((ch = getchar()) != STOP)
{
if (ch == '.')
{
putchar('!');
n++;
}
else if (ch == '!')
{
printf("!!");
n++;
}
else
{
putchar(ch);
}
}
printf("\nTotal replace %d times.\n", n);
printf("('.'->'!') or ('!'->'!!').\n");
return 0;
}
//-------------
//7.12 - 5.c
#include <stdio.h>
#define STOP '#'
int main(void)
{
int ch;
int n = 0;
printf("Enter some characters('#' to quit):\n");
while ((ch = getchar()) != STOP)
{
switch (ch)
{
case '.':
{
putchar('!');
n++;
break;
}
case '!':
{
printf("!!");
n++;
break;
}
default:
{
putchar(ch);
}
}
}
printf("\nTotal replace %d times.\n", n);
printf("('.'->'!') or ('!'->'!!').\n");
return 0;
}
//-------------
//7.12 - 6.c
#include <stdio.h>
#define STOP '#'
int main(void)
{
int ch;
int n = 0;
int flag = 0;
printf("Enter some characters('#' to quit):\n");
while ((ch = getchar()) != STOP)
{
switch (ch)
{
case 'e':
{
flag = 1;
//↑保存一个出现e的标记;
break;
}
case 'i':
{
if (1 == flag)
{
n++;
}
//↑统计ei出现的次数;
flag = 0;
break;
}
default:
{
flag = 0;
//↑如果e的下一个字符不是i则清除标记;
}
}
}
printf("\nTotally exist %d times \'ei\'.\n", n);
return 0;
}
//-------------
//7.12 - 7.c
#include <stdio.h>
#define BASE_SALARY 10.0f
#define EXTRA_HOUR 1.5f
#define BASE_TAX 0.15f
#define EXTRA_TAX 0.2f
#define EXCEED_TAX 0.25f
int main(void)
{
float hours = 0.0f;
float salary, tax, taxed_salary;
printf("Enter the working hours a week: ");
while (scanf("%f", &hours) != 1 || (hours < 0))
{
while (getchar() != '\n')
continue;
printf("Please enter a positive number: ");
}
if (hours <= 30)
{
salary = hours * BASE_SALARY;
tax = salary * BASE_TAX;
taxed_salary = salary - tax;
}
else if (hours <= 40)
{
salary = hours * BASE_SALARY;
tax = 300 * BASE_TAX + (salary - 300) * EXTRA_TAX;
taxed_salary = salary - tax;
}
else
{
salary = (40 + (hours - 40) * EXTRA_HOUR) * BASE_SALARY;
if (salary <= 450)
{
tax = 300 * BASE_TAX + (salary - 300) * EXTRA_TAX;
}
else
{
tax = 300 * BASE_TAX + (salary - 300) * EXTRA_TAX + (salary - 450) * EXCEED_TAX;
}
taxed_salary = salary - tax;
}
printf("salary(before tax): $%g\n", salary);
printf("tax: $%g\n", tax);
printf("salary(after tax): $%g\n", taxed_salary);
return 0;
}
//-------------
//7.12 - 8.c
#include <stdio.h>
#include <ctype.h>
#define EXTRA_HOUR 1.5f
#define BASE_TAX 0.15f
#define EXTRA_TAX 0.2f
#define EXCEED_TAX 0.25f
int show_menu(void);
void show_salary(float base_salary, float hours);
int get_choice(void);
void eatline(void);
int main(void)
{
int ch;
float n;
while ((ch = show_menu()) != 5)
{
printf("Enter the working hours a week: ");
while (scanf("%f", &n) != 1 || (n < 0))
{
eatline();
printf("Enter a positive number: ");
}
eatline();
switch (ch)
{
case 1:
{
show_salary(8.75f, n);
break;
}
case 2:
{
show_salary(9.33f, n);
break;
}
case 3:
{
show_salary(10.00f, n);
break;
}
case 4:
{
show_salary(11.20f, n);
break;
}
}
putchar('\n');
}
printf("Done!\n");
return 0;
}
int get_choice(void)
{
int ch;
scanf("%d", &ch);
eatline();
return ch;
}
void eatline(void)
{
while (getchar() != '\n')
continue;
return;
}
int show_menu(void)
{
int ch;
printf("**********************************************************************\n");
printf("Enter the number corresponding to the desired pay rate or action:\n");
printf("1) $8.75/hr 2) $9.33/hr\n");
printf("3) $10.00/hr 4) $11.20/hr\n");
printf("5) Quit\n");
printf("**********************************************************************\n");
printf("Please you choose: ");
ch = get_choice();
while (ch != 1 && ch != 2 && ch != 3 && ch != 4 && ch != 5)
{
printf("Please enter 1, 2, 3, 4 or 5: ");
ch = get_choice();
}
return ch;
}
void show_salary(float base_salary, float hours)
{
float salary, tax, taxed_salary;
if (hours <= 30)
{
salary = hours * base_salary;
tax = salary * BASE_TAX;
taxed_salary = salary - tax;
}
else if (hours <= 40)
{
salary = hours * base_salary;
tax = 300 * BASE_TAX + (salary - 300) * EXTRA_TAX;
taxed_salary = salary - tax;
}
else
{
salary = (40 + (hours - 40) * EXTRA_HOUR) * base_salary;
if (salary <= 450)
{
tax = 300 * BASE_TAX + (salary - 300) * EXTRA_TAX;
}
else
{
tax = 300 * BASE_TAX + (salary - 300) * EXTRA_TAX + (salary - 450) * EXCEED_TAX;
}
taxed_salary = salary - tax;
}
printf("salary(before tax): $%g\n", salary);
printf("tax: $%g\n", tax);
printf("salary(after tax): $%g\n", taxed_salary);
return;
}
//-------------
//7.12 - 9.c
#include <stdio.h>
#include <math.h>
int main(void)
{
int i, n, number, prime;
printf("Please enter a number (<= 0 to quit): ");
while (scanf("%d", &number) == 1 && (number > 0))
{
if (number == 1)
{
printf("1 isn't a prime!\n");
printf("You can enter again (<= 0 to quit): ");
continue;
}
printf("Here are the prime (<= %d):\n", number);
for (i = 2; i <= number; i++)
{
prime = 1;
for (n = 2; n <= sqrt(i); n++)
{
if (i % n == 0)
{
prime = 0;
break;
}
}
if (prime)
{
printf("%-3d", i);
}
}
printf("\nYou can enter again (<= 0 to quit): ");
}
printf("Done.\n");
return 0;
}
//-------------
//7.12 - 10.c
#include <stdio.h>
#define PLAN1 17850
#define PLAN2 23900
#define PLAN3 29750
#define PLAN4 14875
#define RATE1 0.15
#define RATE2 0.28
int main(void)
{
int n;
double wage, tax;
while (1)
{
printf("********************************\n");
printf("1) single\n");
printf("2) householder\n");
printf("3) married\n");
printf("4) married but divorced\n");
printf("5) quit\n");
printf("********************************\n");
printf("Please you choose: ");
while (scanf("%d", &n) != 1 || (n > 5 || n < 1))
{
while (getchar() != '\n')
continue;
printf("Please enter 1, 2, 3, 4 or 5: ");
}
if (n != 5)
{
printf("Please enter your wage: ");
scanf("%lf", &wage);
}
if (1 == n)
{
if (wage <= PLAN1)
{
tax = wage * RATE1;
}
else
{
tax = PLAN1 * RATE1 + (wage - PLAN1) * RATE2;
}
printf("Your tax: %g\n\n", tax);
}
else if (2 == n)
{
if (wage <= PLAN2)
{
tax = wage * RATE1;
}
else
{
tax = PLAN2 * RATE1 + (wage - PLAN2) * RATE2;
}
printf("Your tax: %g\n\n", tax);
}
else if (3 == n)
{
if (wage <= PLAN3)
{
tax = wage * RATE1;
}
else
{
tax = PLAN3 * RATE1 + (wage - PLAN3) * RATE2;
}
printf("Your tax: %g\n\n", tax);
}
else if (4 == n)
{
if (wage <= PLAN4)
{
tax = wage * RATE1;
}
else
{
tax = PLAN4 * RATE1 + (wage - PLAN4) * RATE2;
}
printf("Your tax: %g\n\n", tax);
}
else if (5 == n)
{
break;
}
}
printf("Done.\n");
return 0;
}
//-------------
//7.12 - 11.c
#include <stdio.h>
#include <ctype.h>
int main(void)
{
const double price_artichokes = 2.05;
const double price_beets = 1.15;
const double price_carrots = 1.09;
const double DISCOUNT_RATE = 0.05;
const double under5 = 6.50;
const double under20 = 14.00;
const double base20 = 14.00;
const double extralb = 0.50;
int ch;
double lb_artichokes = 0;
double lb_beets = 0;
double lb_carrots = 0;
double lb_temp;
double lb_total;
double cost_artichokes;
double cost_beets;
double cost_carrots;
double cost_total;
double final_total;
double discount;
double shipping;
printf("Enter a to buy artichokes, b for beets, ");
printf("c for carrots, q to quit: ");
while ((ch = tolower(getchar())) != 'q')
{
if (isspace(ch))
{
continue;
}
while (getchar() != '\n')
continue;
switch (ch)
{
case 'a':
{
printf("Enter pounds of artichokes: ");
scanf("%lf", &lb_temp);
lb_artichokes += lb_temp;
break;
}
case 'b':
{
printf("Enter pounds of beets: ");
scanf("%lf", &lb_temp);
lb_beets += lb_temp;
break;
}
case 'c':
{
printf("Enter pounds of carrots: ");
scanf("%lf", &lb_temp);
lb_carrots += lb_temp;
break;
}
default:
{
printf("%c is not a valid choice.\n", ch);
}
}
printf("Enter a to buy artichokes, b for beets, ");
printf("c for carrots, q to quit: ");
}
cost_artichokes = price_artichokes * lb_artichokes;
cost_beets = price_beets * lb_beets;
cost_carrots = price_carrots * lb_carrots;
cost_total = cost_artichokes + cost_beets + cost_carrots;
lb_total = lb_artichokes + lb_beets + lb_carrots;
if (lb_total <= 0)
{
shipping = 0.0;
}
else if (lb_total < 5.0)
{
shipping = under5;
}
else if (lb_total < 20.0)
{
shipping = under20;
}
else
{
shipping = base20 + extralb * lb_total;
}
if (cost_total > 100.0)
{
discount = DISCOUNT_RATE * cost_total;
}
else
{
discount = 0.0;
}
final_total = cost_total + shipping - discount;
printf("Your order:\n");
printf("%.2f lbs of artichokes at $%.2f per pound:$ %.2f\n",
lb_artichokes, price_artichokes, cost_artichokes);
printf("%.2f lbs of beets at $%.2f per pound: $%.2f\n",
lb_beets, price_beets, cost_beets);
printf("%.2f lbs of carrots at $%.2f per pound: $%.2f\n",
lb_carrots, price_carrots, cost_carrots);
printf("Total cost of vegetables: $%.2f\n", cost_total);
if (cost_total > 100)
{
printf("Volume discount: $%.2f\n", discount);
}
printf("Shipping: $%.2f\n", shipping);
printf("Total charges: $%.2f\n", final_total);
return 0;
}
//-------------
//-------------------------------------------2020年4月3日 ------------------------------------------