//The code written by this blogger is only for readers' reference;
//If you have any shortcomings, please raise them, and the blogger will do their best to modify;
//Attach the programming practice questions after class;
//If it is useful to you, please like or share it with others;
//8.11 - 1.c
#include <stdio.h>
int main(void)
{
int ch;
int ct = 0;
printf("Please enter some characters:\n");
while ((ch = getchar()) != EOF)
{
ct++;
}
printf("Characters: %d.\n", ct);
return 0;
}
//-------------
//8.11 - 2.c
#include <stdio.h>
int main(void)
{
int ch;
int i = 0;
printf("Please enter some characters:\n");
while ((ch = getchar()) != EOF)
{
if (i++ == 10)
{
putchar('\n');
i = 1;
}
if (ch >= 32) //空格的十进制ASCII码;
{
printf(" \'%c\' - %3d ", ch, ch);
}
else if (ch == '\n')
{
printf(" \\n - \\n\n ");
i = 0;
}
else if (ch == '\t')
{
printf(" \\t - \\t ");
}
else
{
printf(" \'%c\' - ^%c ", ch, ch + 64);
}
}
puts("Done.");
return 0;
}
//-------------
//8.11 - 3.c
#include <stdio.h>
#include <ctype.h>
int main(void)
{
int ch;
unsigned int uct = 0;
unsigned int lct = 0;
unsigned int oct = 0;
printf("Please enter some characters:\n");
while ((ch = getchar()) != EOF)
{
if (isupper(ch))
{
uct++;
}
else if (islower(ch))
{
lct++;
}
else
{
oct++;
}
}
printf("Upper: %u.\n", uct);
printf("Lower: %u.\n", lct);
printf("Others: %u.\n", oct);
return 0;
}
//-------------
//8.11 - 4.c
#include <stdio.h>
#include <ctype.h>
#include <stdbool.h>
int main(void)
{
float count;
bool inword = false;
int ch, words, letter;
words = letter = 0;
printf("Please enter some words (EOF to quit):\n");
while ((ch = getchar()) != EOF)
{
if (ispunct(ch))
{
continue;
}
if (isalpha(ch))
{
letter++;
}
if (!isspace(ch) && !inword)
{
inword = true;
words++;
}
if (isspace(ch) && inword)
{
inword = false;
}
}
count = (float)letter / words;
printf("Total words: %d.\n", words);
printf("Total letters: %d.\n", letter);
printf("Average letters of words: %g.\n", count);
return 0;
}
//-------------
//8.11 - 5.c
#include <stdio.h>
#include <ctype.h>
int main(void)
{
int high = 100;
int low = 1;
int guess = (high + low) / 2;
int response;
printf("Pick an integer from 1 to 100. I will try to guess ");
printf("it.\nRespond with a y if my guess is right, with");
printf("\na h if it is high, and with an l if it is low.\n");
printf("Uh...is your number %d?\n", guess);
while ((response = getchar()) != 'y')
{
if (response == '\n')
{
continue;
}
if (tolower(response) != 'h' && tolower(response) != 'l')
{
printf("I don't understand that response. Please enter h for\n");
printf("high, l for low, or y for correct.\n");
continue;
}
if (tolower(response) == 'h')
{
high = guess - 1;
}
else if (tolower(response) == 'l')
{
low = guess + 1;
}
guess = (high + low) / 2;
printf("Well, then, is it %d?\n", guess);
}
printf("I knew I could do it!\n");
return 0;
}
//-------------
//8.11 - 6.c
#include <stdio.h>
#include <ctype.h>
#define STOP '#'
int get_first(void);
int main(void)
{
int ch;
printf("Please enter some characters ('#' to quit):\n");
while ((ch = get_first()) != STOP)
{
printf("Result: %c\n", ch);
printf("You can enter again ('#' to quit):\n");
}
printf("Done.\n");
return 0;
}
int get_first(void)
{
int ch;
do
{
ch = getchar();
} while (isspace(ch));
while (getchar() != '\n')
continue;
return ch;
}
//-------------
//8.11 - 7.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()) != 'q')
{
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("%c", &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("a) $8.75/hr b) $9.33/hr\n");
printf("c) $10.00/hr d) $11.20/hr\n");
printf("q) Quit\n");
printf("**********************************************************************\n");
printf("Please you choose: ");
ch = get_choice();
while (ch != 'a' && ch != 'b' && ch != 'c' && ch != 'd' && ch != 'q')
{
printf("Please enter a, b, c, d or q: ");
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;
}
//-------------
//8.11 - 8.c
#include <stdio.h>
#include <math.h>
#include <ctype.h>
#include <string.h>
int get_first(void);
int get_choice(void);
float get_float(void);
int main(void)
{
int ct;
float i, j;
while ((ct = get_choice()) != 'q')
{
printf("Enter first number: ");
i = get_float();
printf("Enter second number: ");
j = get_float();
switch (ct)
{
case 'a':
{
printf("%g + %g = %g\n", i, j, i + j);
break;
}
case 's':
{
printf("%g - %g = %g\n", i, j, i - j);
break;
}
case 'm':
{
printf("%g * %g = %g\n", i, j, i * j);
break;
}
case 'd':
{
while (fabs(j) <= 1e-6)
{
//↑判断float型浮点数是否为0;
printf("Enter a number other than 0: ");
j = get_float();
}
printf("%g / %g = %g\n", i, j, i / j);
break;
}
}
}
printf("Bye.\n");
return 0;
}
int get_first(void)
{
int ch;
do
{
ch = tolower(getchar());
} while (isspace(ch));
while (getchar() != '\n')
continue;
return ch;
}
int get_choice(void)
{
int ch;
printf("Enter the operation of your choice:\n");
printf("a. add s. subtract\n");
printf("m. multiply d. divide\n");
printf("q. quit\n");
ch = get_first();
while (ch != 'a' && ch != 's' && ch != 'm' && ch != 'd' && ch != 'q')
{
printf("Please enter with a,s,m,d or q :");
ch = get_first();
}
return ch;
}
float get_float(void)
{
int ch;
float input;
while (scanf("%f", &input) != 1)
{
while ((ch = getchar()) != '\n')
{
putchar(ch);
}
printf(" is not an number.\n");
printf("Please enter a number such as 2.5, -1.78E8 or 3: ");
}
return input;
}
//-------------
//----------------------------April 3, 2020-------------- -----------------