編程練習七

第12章存儲類、鏈接和內存管理

c primer plus 課本P352中第2、3、4、5、6、7題

第2題：

<span style="font-size:18px;">//Pel2-2a.h:
#include <stdio.h>
#define METRIC 0
#define US 1
 
void set_mode(int m);
void get_info();
void show_info();</span>

<span style="font-size:18px;">//Pel2-2a.c:
#include <stdio.h>
#include "pel2-2a.h"
 
static int mode=METRIC;
static int distance;
static double fuel;
void set_mode(int m)
{
    mode=m;
    if((m==METRIC)||(m==US))
        ;
    else
        printf("Invalid mode specified. Mode %s used.\n", m == METRIC ? "0(METRIC)" : "1(US)");
 
}
 
void get_info()
{
    if (mode==METRIC)
    {
        printf("enter distance traveled in kilometers:");
        scanf("%d",&distance);
        printf("enter fuel consumed in liters:");
 
        scanf("%lf",&fuel);
        //printf("%f\n",fuel);
        //printf("%lf\n",fuel); 這裏如果使用%lf，會出問題，打印0.000
 
    }
    else
    {
        printf("enter distance traveled in miles:");
        scanf("%d",&distance);
        printf("enter fuel consumed in gallons:");
        scanf("%lf",&fuel);
 
    }
}
 
void show_info()
{
   // printf("%d\n",distance);
    //printf("%f\n",fuel);
    if(mode==METRIC)
        printf("fuel consumption is %.2f liters per 100 km\n.",(fuel/distance)*100);
    else
        printf("fuel consumption is %.2f miles per gallon.\n",distance/fuel);
}</span>

<span style="font-size:18px;">//主函數：
#include <stdio.h>
#include "pel2-2a.h"
int main()
{
    int mode;
    printf("Enter 0 for metric mode, 1 for US mode:");
    scanf("%d",&mode);
    while(mode>=0)
    {
        set_mode(mode);
        get_info();
        show_info();
        printf("Enter 0 for metric mode, 1 for US mode");
        printf("(-1 to quit):");
        scanf("%d",&mode);
    }
    printf("Done. \n");
   return 0;
}</span>

第三題：

 

#include <stdio.h>
int set_mode();
void get_info(int m,int *d,double *f);
void show_info(int m,int d,double f);
 
int main()
{
    int mode;
    int distance;
    double fuel;
    mode=set_mode();
    while (mode>=0)
    {
        get_info(mode,&distance,&fuel);
        show_info(mode,distance,fuel);
        printf("Enter 0 for metric mode, 1 for US mode");
        printf(" (-1 to quit): ");
        scanf("%d", &mode);
    }
    printf("Done.\n");
    return 0;
}
 
 
int set_mode()
{
    int m;
    printf("Enter 0 for metric mode, 1 for US mode: ");
    scanf("%d",&m);
    if (m==0||m==1);
    else
        printf("Invaild mode specificed. Mode %s used\n",m == 0 ? "0(METRIC)" : "1(US)");
    return m;
}
void get_info(int m,int *d,double *f)
{
    if(m==0)
    {
        printf("enter distance traveled in kilometers:");
        scanf("%d",d);
        printf("enter fuel consumed in liters:");
 
        scanf("%lf",f);
 
    }
    else
    {
        printf("enter distance traveled in miles:");
        scanf("%d",d);
        printf("enter fuel consumed in gallons:");
        scanf("%lf",f);
 
    }
}
void show_info(int m,int d,double f)
{
    if(m==0)
        printf("fuel consumption is %.2f liters per 100 km\n.",(f/d*100));
    else
        printf("fuel consumption is %.2f miles per gallon.\n",(d/f));
}

4.編寫一個函數,返回自身被調用的次數

<span style="font-size:18px;">#include<stdio.h>
int n;
int fun()
{
   n++;
   return n;
}
 
int main()
{
   int i;
   for(i=1;i<=10;i++)
   {
     printf("函數被調用%d次\n",fun());
   }
   return 0;
}</span>

5.編寫產生100個1到10範圍內的隨機數的程序，並且以降序排序。

 

/*編寫產生100個1到10範圍內的隨機數的程序，並且以降序排序*/
 
#include <stdio.h>
 
void funsort(int *);
 
int main()
{
    int i;
    int a[100];
    for(i=0; i<100; i++)
    {
        a[i]=rand()%10+1;
        printf("%3d",a[i]);
        if(i%10==9)
            printf("\n");
    }
    funsort(&a);
    printf("\n");
    printf("排序後的數組爲：\n");
    for(i=0; i<100; i++)
    {
        printf("%3d",a[i]);
        if(i%10==9)
            printf("\n");
    }
 
    return 0;
}
void funsort(int *a)
{
    int k,t;
    int temp;
    for(k=0; k<100; k++)
    {
        for(t=k+1; t<100; t++)
        {
            if(a[k]<a[t])
            {
                temp=a[t];
                a[t]=a[k];
                a[k]=temp;
            }
        }
    }
}

6.編寫一個產生1000個1到10範圍內的隨機數的程序。不必保存或打印數字，僅打印數字被產生的次數。

<span style="font-size:18px;">#include <stdio.h>
 
int main()
{
    int i,j;
    int a[1000];
    int k[11]= {0};
    for(i=0; i<1000; i++)
    {
        a[i]=rand()%10+1;
        //printf("%3d",a[i]);
        k[a[i]]++;
        if(i%10==9)
            printf("\n");
    }
    for(j=1; j<11; j++)
    {
        printf("%d 被產生了 %d 次\n",j,k[j]);
    }
    printf("\n");
    return 0;
}</span>

7.編寫一個程序，輸出如下：

Enter the number of sets; enter q to stop.

  18

 How many sides and how many dice?

  6 3

Here are 18 sets of 3 6-side throws.

 12 10 6 9 8 14 8 15 9 14 12 17 11 7 10

 13 8 14

How many sets? Enter q to stop.

<span style="font-size:18px;">#include <stdio.h>
#include <stdlib.h>    /* for srand() */
#include <time.h>     /* for time() */</span>

<span style="font-size:18px;">
int rollem(int);</span>

<span style="font-size:18px;">
int main()
{
    int dice, count, roll;
    int sides;
    int set, sets;
    srand((unsigned int) time(0)); /* randomize rand() */
    printf("Enter the number of sets; enter q to stop.\n");
    while ( scanf("%d", &sets) == 1)
    {
        printf("How many sides and how many dice?\n");
        scanf("%d %d", &sides, &dice);
        printf("Here are %d sets of %d %d-sided throws.\n", sets, dice,
               sides);
        for (set=0;set<sets;set++)
        {
            for (roll=0,count=0;count<dice;count++)
                roll+=rollem(sides);
            /* running total of dice pips */
            printf("%4d ",roll);
            if (set%15==14)
                putchar('\n');
        }
        if (set%15!=0)
            putchar('\n');
        printf("How many sets? Enter q to stop.\n");
    }
    return 0;
}</span>

<span style="font-size:18px;">
int rollem(int sides)
{
    int roll;
    roll=rand()%sides+1;
    return roll;
}
</span>