selsolutionsc5.txt

primer c 5th edition 一书详细叙述了c语言的概念和知识。包括17章内容

         else
         {
             sumeven += n;
             ++ct_even;
         }
     }
     printf("Number of evens: %d", ct_even);
     if (ct_even > 0)
         printf("  average: %g", sumeven / ct_even);
     putchar('\n');
         
    printf("Number of odds: %d", ct_odd);
     if (ct_odd > 0)
         printf("  average: %g", sumodd / ct_odd);
     putchar('\n');
     printf("\ndone\n");
     
    return 0;
}

PE 7-5
 
/* Programming Exercise 7-5 */
#include <stdio.h>

int main(void)    
{
     char ch;
     int ct1 = 0;
     int ct2 = 0;
     
     while ((ch = getchar()) != '#')
     {
         switch(ch)
         {
              case '.'    :  putchar('!');
                             ++ct1;
                             break;

              case '!'    :  putchar('!');
                             putchar('!');
                             ++ct2;
                             break;
             default    :    putchar(ch);
         }
     }
     printf("%d replacements of . with !\n", ct1);
     printf("%d replacements of ! with !!\n", ct2);
      
    return 0;
}

PE 7-7
 
/* Programming Exercise 7-7 */
#include <stdio.h>

#define BASEPAY     10      /* $10 per hour         */
#define BASEHRS     40      /* hours at basepay     */
#define OVERTIME    1.5     /* 1.5 time             */
#define AMT1        300     /* 1st rate tier        */
#define AMT2        150     /* 2st rate tier        */
#define RATE1       0.15    /* rate for 1st tier    */
#define RATE2       0.20    /* rate for 2nd tier    */
#define RATE3       0.25    /* rate for 3rd tier    */
int main(void)    
{
    double hours;
    double gross;
    double net;
    double taxes;
    
    printf("Enter the number of hours worked this week: ");
    scanf("%lf", &hours);
    if (hours <= BASEHRS)
        gross = hours * BASEPAY;
    else
        gross = BASEHRS * BASEPAY + (hours - BASEHRS) * BASEPAY * OVERTIME;
    if (gross <= AMT1)
        taxes = gross * RATE1;
    else if (gross <= AMT1 + AMT2)
        taxes = AMT1 * RATE1 + (gross - AMT1) * RATE2;
    else
        taxes = AMT1 * RATE1 + AMT2 * RATE2 + (gross - AMT1 - AMT2) * RATE3;
    net = gross - taxes;
    printf("gross: $%.2f; taxes: $%.2f; net: $%.2f\n", gross, taxes, net);
      
    return 0;
}

PE 7-9
 
/* Programmming Exercise 7-9 */
#include <stdio.h>
#define NO 0
#define YES 1
int main(void)
{
   long num;                      /* value to be checked */
   long div;                      /* potential divisors  */
   long lim;                      /* limit to values     */
   int prime;

   printf("Please enter limit to values to be checked; ");
   printf("Enter q to quit.\n");
   while (scanf("%ld", &lim) == 1 && lim > 0)
   {
         for (num = 2; num <= lim; num++)
         {               
          for (div = 2, prime = YES; (div * div) <= num; div++)
             if (num % div == 0)
                prime = NO;           /* number is not prime  */
          if (prime == YES)
             printf("%ld is prime.\n", num);
      }
      printf("Please enter another limit; ");
      printf("Enter q to quit.\n");
   }
   return 0;
}

PE 7-11
 
/* pe7-11.c */
/* Programming Exercise 7-11 */
#include <stdio.h>
#include <ctype.h>
int main(void)
{
  const double price_artichokes = 1.25;
  const double price_beets = 0.65;
  const double price_carrots = 0.89;
  const double DISCOUNT_RATE = 0.05;
  
  char ch;
  double lb_artichokes;
  double lb_beets;
  double lb_carrots;
  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 = getchar()) != 'q' && ch != 'Q')
  {
      if (ch == '\n')
          continue;
      while (getchar() != '\n')
          continue;
       ch = tolower(ch);
      switch (ch)
      {
          case 'a' : printf("Enter pounds of artichokes: ");
                   scanf("%lf", &lb_artichokes);
                   break;
           case 'b' : printf("Enter pounds of beets: ");
                   scanf("%lf", &lb_beets);
                   break;
     
           case 'c' : printf("Enter pounds of carrots: ");
                   scanf("%lf", &lb_carrots);
                   break;
        default  : printf("%c is not a valid choice.\n");
    }
    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 = 3.50;
  else if (lb_total < 20)
      shipping = 10.0;
  else
      shipping =  8.0 + 0.1 * 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;
}

Chapter 8

PE 8-1
 
/* Programming Exercise 8-1 */

#include <stdio.h>
int main(void)
{
    int ch;
    int ct = 0;
    
    while ((ch = getchar()) != EOF)
        ct++;
    printf("%d characters read\n", ct);
    
    return 0;
}

PE 8-3
 
/* Programming Exercise 8-3 */
/* Using ctype.h eliminates need to assume ASCII coding */
#include <stdio.h>
#include <ctype.h>
int main(void)
{
    int ch;
    int uct = 0;
    int lct = 0;
    
    while ((ch = getchar()) != EOF)
        if (isupper(ch))
            uct++;
        else if (islower(ch))
            lct++;
    printf("%d uppercase characters read\n", uct);
    printf("%d lowercase characters read\n", lct);
    
    return 0;
}

/*
 or you could use
 if (ch >= 'A' && ch <= 'Z')
     uct++;
 else if (ch >= 'a' && ch <= 'z')
     lct++;
*/

PE 8-5

/* Programming Exercise 8-5 */
/* binaryguess.c -- an improved number-guesser */
#include <stdio.h>
#include <ctype.h>
int main(void)
{
  int high = 100;
  int low = 1;
  int guess = (high + low) / 2;
  char 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')       /* get response */
  {
      if (response == '\n')
          continue;
      if (response != 'h' && 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 (response == 'h')
          high = guess - 1;
      else if (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;
}

PE 8-7
 
/* Programming Exercise 8-7 */
#include <stdio.h>
#include <ctype.h>

#define BASEPAY1    8.75    /* $8.75 per hour       */
#define BASEPAY2    9.33    /* $9.33 per hour       */
#define BASEPAY3    10.00   /* $10.00 per hour      */
#define BASEPAY4    11.20   /* $11.20 per hour      */
#define BASEHRS     40      /* hours at basepay     */
#define OVERTIME    1.5     /* 1.5 time             */
#define AMT1        300     /* 1st rate tier        */
#define AMT2        150     /* 2st rate tier        */
#define RATE1       0.15    /* rate for 1st tier    */
#define RATE2       0.20    /* rate for 2nd tier    */
#define RATE3       0.25    /* rate for 3rd tier    */

int getfirst(void); 
void menu(void);

int main(void)    
{
    double hours;
    double gross;
    double net;
    double taxes;
    double pay;
    char response;
    
    
    menu();
    while ((response = getfirst()) != 'q')
    {
        if (response == '\n')            /* skip over newlines     */
            continue;
        response = tolower(response);   /* accept A as a, etc.    */
        switch (response)
        {
            case 'a'  :  pay = BASEPAY1; break;
            case 'b'  :  pay = BASEPAY2; break;
            case 'c'  :  pay = BASEPAY3; break;
            case 'd'  :  pay = BASEPAY4; break;
            default   :  printf("Please enter a, b, c, d, or q.\n");
                         menu();
                         continue;   /* go to beginning of loop */
        }    
        printf("Enter the number of hours worked this week: ");    
        scanf("%lf", &hours);
        if (hours <= BASEHRS)
            gross = hours * pay;
        else
            gross = BASEHRS * pay + (hours - BASEHRS) * pay * OVERTIME;
        if (gross <= AMT1)
            taxes = gross * RATE1;
        else if (gross <= AMT1 + AMT2)
            taxes = AMT1 * RATE1 + (gross - AMT1) * RATE2;
        else
            taxes = AMT1 * RATE1 + AMT2 * RATE2 + (gross - AMT1 - AMT2) *
                    RATE3;
        net = gross - taxes;
        printf("gross: $%.2f; taxes: $%.2f; net: $%.2f\n", gross, taxes,
                net);
        menu();
    }
    printf("Done.\n");
      
    return 0;
}

void menu(void)
{
    printf("********************************************************"
           "*********\n");
    printf("Enter the number corresponding to the desired pay rate"
           " or action:\n");
    printf("a)  $%4.2f/hr                b)  $%4.2f/hr\n", BASEPAY1,
            BASEPAY2);
    printf("c) $%5.2f/hr                d) $%5.2f/hr\n", BASEPAY3,
            BASEPAY4);
    printf("q) quit\n");
    printf("********************************************************"
           "*********\n");
}

int getfirst(void) 
{ 
    int ch; 
 
    ch = getchar();
    while (isspace(ch))
        ch = getchar(); 
    while (getchar() != '\n') 
        continue; 
    return ch; 
} 

Chapter 9
PE 9-1

/* Programming Exercise 9-1 */
#include <stdio.h>

double min(double a, double b);
int main(void)    
{
    double x, y;
    
    printf("Enter two numbers (q to quit): ");
    while (scanf("%lf %lf", &x, &y) == 2)
    {
        printf("The smaller number is %f.\n", min(x,y));
        printf("Next two values (q to quit): ");
    }
    printf("Bye!\n");
      
    return 0;
}

double min(double a, double b)
{
    return a < b ? a : b;

}
/* alternative implementation
double min(double a, double b)
{
    if (a < b)
        return a;
    else
        return b;
}
*/

PE 9-3

/* Programming Exercise 9-3 */
#include <stdio.h>

void chLineRow(char ch, int c, int r);
int main(void)    
{
    char ch;
    int col, row;
    
    printf("Enter a character (# to quit): ");
    while ( (ch = getchar()) != '#')
    {
        if (ch == '\n')
            continue;
        printf("Enter number of columns and number of rows: ");
        if (scanf("%d %d", &col, &row) != 2)
            break;
        chLineRow(ch, col, row);
        printf("\nEnter next character (# to quit): ");
    }
    printf("Bye!\n");
      
    return 0;
}

void chLineRow(char ch, int c, int r)
{
    int col, row;

    for (row = 0; row < r ; row++)
    {
        for (col = 0; col < c; col++)
            putchar(ch);
        putchar('\n');
    }
    return;
}

PE 9-5

/* Programming Exercise 9-5 */
#include <stdio.h>

void larger_of(double *p1, double *p2);
int main(void)    
{
    double x, y;
    
    printf("Enter two numbers (q to quit): ");
    while (scanf("%lf %lf", &x, &y) == 2)
    {
        larger_of(&x, &y);
        printf("The modified values are %f and %f.\n", x, y);
        printf("Next two values (q to quit): ");
    }
    printf("Bye!\n");
      
    return 0;
}

void larger_of(double *p1, double *p2)
{
    double temp = *p1 > *p2 ? *p1 : *p2;
    *p1= *p2 = temp;
}

PE 9-7

/* Programming Exercise 9-7 */
#include <stdio.h>
double power(double a, int b);  /* ANSI prototype */
int main(void)
{
  double x, xpow;
  int n;

  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, &n) == 2)
  {
       xpow = power(x,n);       /* function call           */
       printf("%.3g to the power %d is %.5g\n", x, n, 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 a, int b)   /* function definition     */
{
  double pow = 1;
  int i;
  
  if (b == 0)
  {
      if (a == 0)
          printf("0 to the 0 undefined; using 1 as the value\n");
      pow = 1.0;
  }
  else if (a == 0)
      pow = 0.0;
  else if (b > 0)
      for(i = 1; i <= b; i++)
       pow *= a;
  else    /* b < 0 */
      pow = 1.0 / power(a, - b);
  return pow;                  /* return the value of pow  */
}


PE 9-9

/* Programming Exercise 9-9 */
#include <stdio.h>
void to_base_n(int x, int base);
int main(void)
{
  int number;
  int b;
  
  printf("Enter an integer (q to quit):\n");
  while (scanf("%d", &number) == 1)
  {
       printf("Enter number base (2-10): ");
       scanf("%d", &b);
     printf("Base %d equivalent: ", b);
     to_base_n(number, b);
     putchar('\n');
     printf("Enter an integer (q to quit):\n");
  }
  return 0;
}
void to_base_n(int x, int base)   /* recursive function */