//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；
//9.11 - 1.c
#include <stdio.h>
double min(double x, double y);
int main(void)
{
double a, b;
printf("Please enter two numbers (q to quit): ");
while (scanf("%lf %lf", &a, &b) == 2)
{
printf("Minimum: %g\n", min(a, b));
printf("You can enter again (q to quit): ");
}
printf("Done.\n");
return 0;
}
double min(double x, double y)
{
return x < y ? x : y;
}
//-------------
//9.11 - 2.c
#include <stdio.h>
#define CHAR '#'
void chline(int ch, int cols, int rows);
int main(void)
{
int i, j;
printf("Please enter two numbers (q to quit): ");
while (scanf("%d %d", &j, &i) == 2)
{
printf("Printing %c in %d rows and %d columns is:\n", CHAR, j, i);
chline(CHAR, i, j);
printf("You can enter two numbers again (q to quit): ");
}
printf("Done.\n");
return 0;
}
void chline(int ch, int cols, int rows)
{
int a, b;
for (a = 1; a <= rows; a++)
{
for (b = 1; b <= cols; b++)
{
putchar(ch);
}
putchar('\n');
}
return;
}
//-------------
//9.11 - 3.c
#include <stdio.h>
#define CHAR '#'
void show(int ch, int cols, int rows);
int main(void)
{
int i, j;
printf("Please enter two numbers (q to quit): ");
while (scanf("%d %d", &j, &i) == 2)
{
printf("Printing %c in %d rows and %d columns is:\n", CHAR, i, j);
show(CHAR, j, i);
printf("You can enter two numbers again (q to quit): ");
}
printf("Done.\n");
return 0;
}
void show(int ch, int cols, int rows)
{
int a, b;
for (a = 1; a <= rows; a++)
{
for (b = 1; b <= cols; b++)
{
putchar(ch);
}
putchar('\n');
}
return;
}
//-------------
//9.11 - 4.c
#include <stdio.h>
double harmean(double x, double y);
int main(void)
{
double a, b;
printf("Please enter two numbers (q to quit): ");
while (scanf("%lf %lf", &a, &b) == 2)
{
printf("The harmonic mean of %g and %g is %g\n", a, b, harmean(a, b));
printf("You can enter two numbers again (q to quit): ");
}
printf("Done.\n");
return 0;
}
double harmean(double x, double y)
{
return 2 / (1 / x + 1 / y);
}
//-------------
//9.11 - 5.c
#include <stdio.h>
void larger_of(double *x, double *y);
int main(void)
{
double a, b;
printf("Please enter two numbers (q to quit): ");
while (scanf("%lf %lf", &a, &b) == 2)
{
larger_of(&a, &b);
printf("Results: %g and %g\n", a, b);
printf("You can enter two numbers again (q to quit): ");
}
printf("Done.\n");
return 0;
}
void larger_of(double *x, double *y)
{
*x = *y = *x > *y ? *x : *y;
return;
}
//-------------
//9.11 - 6.c
#include <stdio.h>
void test(double *a, double *b, double *c);
int main(void)
{
double x, y, z;
printf("Please enter three numbers (q to quit): ");
while (scanf("%lf %lf %lf", &x, &y, &z) == 3)
{
test(&x, &y, &z);
printf("Min: %g\n", x);
printf("Middle: %g\n", y);
printf("Max: %g\n", z);
printf("You can enter three numbers again (q to quit): ");
}
printf("Done.\n");
return 0;
}
void test(double *a, double *b, double *c)
{
double tp;
if (*a > *b)
{
tp = *a;
*a = *b;
*b = tp;
}
if (*a > *c)
{
tp = *a;
*a = *c;
*c = tp;
}
if (*b > *c)
{
tp = *b;
*b = *c;
*c = tp;
}
return;
}
//-------------
//9.11 - 7.c
#include <stdio.h>
#include <ctype.h>
void attain_pos(void);
int position(int ch);
int main(void)
{
attain_pos();
return 0;
}
void attain_pos(void)
{
int ch;
int figure;
printf("Please enter a character (EOF to quit):\n");
while ((ch = getchar()) != EOF)
{
figure = position(ch);
if (figure)
{
printf("%c is %d in alphabet.\n", ch, figure);
}
else
{
printf("%c isn't a letter!\n", ch); //包括回车换行符和空白符;
}
while (getchar() != '\n')
continue;
printf("You can enter again (EOF to quit): ");
}
printf("Done.\n");
}
int position(int ch)
{
if (isupper(ch))
{
return (ch - 'A' + 1);
}
else if (islower(ch))
{
return (ch - 'a' + 1);
}
return 0;
}
//-------------
//9.11 - 8.c
#include <stdio.h>
double power(double n, int p);
int main(void)
{
double x, xpow;
int exp;
printf("Enter a number and the integer power");
printf(" to which\nthe number will be raised. Enter q");
printf(" to quit.\n");
while (scanf("%lf %d", &x, &exp) == 2)
{
xpow = power(x, exp);
printf("%.3g to the power %d is %.5g.\n", x, exp, xpow);
printf("Enter next pair of numbers or q to quit.\n");
}
printf("Hope you enjoyed this power trip -- bye!\n");
return 0;
}
double power(double n, int p)
{
int i;
double pow = 1.0;
if ((0 == p) && (0 == n))
{
printf("0 to the 0 undefined, using 1 as the value.\n");
return pow;
}
if (0 == n)
{
pow = 0.0;
return pow;
}
if (0 == p)
{
return pow;
}
if (p > 0)
{
for (i = 1; i <= p; i++)
{
pow *= n;
}
return pow;
}
else
{
for (i = 1; i <= -p; i++)
{
pow *= 1 / n;
}
return pow;
}
}
//-------------
//9.11 - 9.c
#include <stdio.h>
double power(double n, int p);
int main(void)
{
double x, xpow;
int exp;
printf("Enter a number and the integer power");
printf(" to which\nthe number will be raised. Enter q");
printf(" to quit.\n");
while (scanf("%lf %d", &x, &exp) == 2)
{
xpow = power(x, exp);
printf("%.3g to the power %d is %.5g.\n", x, exp, xpow);
printf("Enter next pair of numbers or q to quit.\n");
}
printf("Hope you enjoyed this power trip -- bye!\n");
return 0;
}
double power(double n, int p)
{
double pow = 1.0;
if ((0 == p) && (0 == n))
{
printf("0 to the 0 undefined, using 1 as the value.\n");
return pow;
}
if (0 == n)
{
pow = 0.0;
return pow;
}
if (0 == p)
{
return pow;
}
if (p > 0)
{
return n * power(n, p - 1);
}
else
{
return power(n, p + 1) / n;
}
}
//-------------
//9.11 - 10.c
#include <stdio.h>
void to_base_n(int x, int base);
int main(void)
{
int b;
long int n;
printf("Please enter a number (q to quit): ");
while (scanf("%ld", &n) == 1)
{
if (n <= 0)
{
printf("Illegal data! Please enter again: ");
continue;
}
printf("Please enter a base system number (2 - 10): ");
while (scanf("%d", &b) != 1 || (b < 2 || b > 10))
{
while (getchar() != '\n')
continue;
printf("Please enteragain (2 - 10): ");
}
printf("%d in %d base system is: ", n, b);
to_base_n(n, b);
printf("\nYou can enter a number again (q to quit): ");
}
printf("Done.\n");
return 0;
}
void to_base_n(int x, int base)
{
int r;
r = x % base;
if (x >= base)
{
to_base_n(x / base, base);
}
printf("%d", r);
return;
}
//-------------
//9.11 - 11.c
#include <stdio.h>
void Fibonacci(int len);
int main(void)
{
int n;
printf("Please enter a integer (<= 0 or q to quit): ");
while (scanf("%d", &n) == 1)
{
printf("Top %d items of Fibonacci sequence:\n", n);
Fibonacci(n);
printf("You can enter again (<= 0 or q to quit): ");
}
printf("Done.\n");
return 0;
}
void Fibonacci(int len)
{
int i;
unsigned long t, x, y;
x = y = 1;
for (i = 0; i < len; i++)
{
printf("%lu\n", x);
t = x + y;
x = y;
y = t;
}
return;
}
//-------------
//----------------------------2020年4月4日 -------------------------------
//致敬英雄，缅怀同胞，愿山河无恙，人间皆安！