c primer plus 12 编程练习

1、

#include <stdio.h>

void critic(int * ar1);

int main(void)
{
    int num;
    
    printf("how many pounds to a firkin of butter? 
");
    scanf("%d", &num);
    
    while(num != 56)
        critic(&num);
    
    printf("you must have looked the answer!
");
    
    return 0;
}

void critic(int * ar1)
{
    printf("wrong, try again!
");
    scanf("%d", ar1);
}

#include <stdio.h>

void critic(int * n);

int main(void)
{
    int units;
    
    printf("how many pounds to a firkin of butter?
");
    scanf("%d", &units);
    
    while(units != 56)
        critic(&units);
        
    printf("you must have looked it up!
");
    
    return 0;    
} 

void critic(int * n)
{
    printf("No luck, my friends, try again.
");
    scanf("%d", n);
}

2、

[root@centos79 test2]# cat pe12-2a.c
#include <stdio.h>

int mode;
double distance;
double fuel;

void set_mode(int ar1)
{
        if(ar1 > 1)
        {
                ar1 == 1;
                printf("Invalid mode specified. Mode 1(US) used.
");
        }
}

void get_info(void)
{
        if(mode == 0)
        {
                printf("Enter distance traveled in kilometers: ");
                scanf("%lf", &distance);
                printf("Enter fuel consumed in liters: ");
                scanf("%lf", &fuel);
        }
        else
        {
                printf("Enter distance traveled in miles: ");
                scanf("%lf", &distance);
                printf("Enter fuel consumed in gallons: ");
                scanf("%lf", &fuel);
        }
}

void show_info(void)
{
        if(mode == 0)
        {
                printf("Fuel xonsumption is %.2f liters per 100Km
", fuel / distance * 100);
        }
        else
        {
                printf("Fuel consumption is %.2f miles per gallon.
", distance / fuel);
        }
}

[root@centos79 test2]# ls
pe12-2a.c  pe12-2a.h  pe12-2b.c
[root@centos79 test2]# cat pe12-2a.h
extern int mode;
extern double distance;
extern double fuel;
void set_mode(int ar);
void get_info(void);
void show_info(void);

[root@centos79 test2]# ls
pe12-2a.c  pe12-2a.h  pe12-2b.c
[root@centos79 test2]# cat pe12-2b.c
#include <stdio.h>
#include "pe12-2a.h"

int main(void)
{
        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);
        }

        return 0;
}

[root@centos79 test2]# ls
pe12-2a.c  pe12-2a.h  pe12-2b.c
[root@centos79 test2]# gcc *
[root@centos79 test2]# ls
a.out  pe12-2a.c  pe12-2a.h  pe12-2a.h.gch  pe12-2b.c

[root@centos79 test2]# ls
a.out  pe12-2a.c  pe12-2a.h  pe12-2a.h.gch  pe12-2b.c
[root@centos79 test2]# ./a.out
enter 0 for metric mode, 1 for US mode: 0
Enter distance traveled in kilometers: 600
Enter fuel consumed in liters: 78.8
Fuel xonsumption is 13.13 liters per 100Km
enter 0 for metric mode, 1 for us mode (-1 to quit): 1
Enter distance traveled in miles: 434
Enter fuel consumed in gallons: 12.7
Fuel consumption is 34.17 miles per gallon.
enter 0 for metric mode, 1 for us mode (-1 to quit): 3
Invalid mode specified. Mode 1(US) used.
Enter distance traveled in miles: 388
Enter fuel consumed in gallons: 15.3
Fuel consumption is 25.36 miles per gallon.
enter 0 for metric mode, 1 for us mode (-1 to quit): -1

3、

[root@centos79 test2]# ls
h.h  x.c  y.c
[root@centos79 test2]# cat x.c
#include <stdio.h>

void set_mode(int * ar1)
{
        if(*ar1 > 1)
        {
                printf("Invalid mode specified, Mode 1(US) used.
");
                *ar1 = 1;
        }
}

void get_info(int * ar1, double * ar2, double * ar3)
{
        if(*ar1 == 0)
        {
                printf("Enter distance traveled in kilometer: ");
                scanf("%lf", ar2);
                printf("Enter fuel consumed in liters: ");
                scanf("%lf", ar3);
                printf("Fuel consumption is %.2f liters per 100 km.
", *ar3 / *ar2 * 100);
        }
        else
        {
                printf("Enter distance traveled in miles: ");
                scanf("%lf", ar2);
                printf("Enter fule consumed in gallon: ");
                scanf("%lf", ar3);
                printf("Fuel consumption is %.2f mile per gallon.
", *ar2 / *ar3);
        }
}

[root@centos79 test2]# cat y.c
#include <stdio.h>
#include "h.h"

int main(void)
{

        while(1)
        {
                auto int mode;
               double distance, fuel; //自动变量

                printf("Enter 0 for metric mode, 1 for US mode");
                printf(" (-1 to quit): ");
                scanf("%d", &mode);
                if(mode < 0)
                        break;

                set_mode(&mode);
                get_info(&mode, &distance, &fuel);

        }
        printf("Done,
");

        return 0;
}

[root@centos79 test2]# cat h.h
extern void set_mode(int * ar1);

extern void get_info(int * ar1, double * ar2, double * ar3);

[root@centos79 test2]# ls
h.h  x.c  y.c
[root@centos79 test2]# gcc *
[root@centos79 test2]# ls
a.out  h.h  h.h.gch  x.c  y.c

[root@centos79 test2]# ls
a.out  h.h  h.h.gch  x.c  y.c
[root@centos79 test2]# ./a.out
Enter 0 for metric mode, 1 for US mode (-1 to quit): 0
Enter distance traveled in kilometer: 600
Enter fuel consumed in liters: 78.8
Fuel consumption is 13.13 liters per 100 km.
Enter 0 for metric mode, 1 for US mode (-1 to quit): 1
Enter distance traveled in miles: 434
Enter fule consumed in gallon: 12.7
Fuel consumption is 34.17 mile per gallon.
Enter 0 for metric mode, 1 for US mode (-1 to quit): 3
Invalid mode specified, Mode 1(US) used.
Enter distance traveled in miles: 388
Enter fule consumed in gallon: 15.3
Fuel consumption is 25.36 mile per gallon.
Enter 0 for metric mode, 1 for US mode (-1 to quit): -1
Done,

4、

#include <stdio.h>

int invoke(void);
int times = 0;

int main(void)
{
    int i;
    
    for(i = 1; i <= 5; i++)
    {
        invoke();
    }
    printf("times: %d
", times);
    
    return 0;
}

int invoke(void)
{
    printf("hello world!
");;
    times++;
　　return times;
}

#include <stdio.h>

static int count = 0;

int run_counter(void);

int main(void)
{
    int i;
    
    for(i = 1; i <= 5; i++)
    {
        printf("The function run_time run %d times.
", run_counter());
    }
    
    return 0;
}

int run_counter(void)
{
    return ++count;    
} 

5、

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main(void)
{
    int max;
    int num;
    int i;
    
    printf("please input the max: "); scanf("%d", &max);
    printf("please input the num: "); scanf("%d", &num);
    
    srand((unsigned int) time(0));

    for(i = 1; i <= 10; i++)
    {
        printf("%3dst: %d
", i, rand() % 10 + 1);
    }    
    
    return 0;
} 

#include <stdio.h>
#define NUM 5

int main(void)
{
    int ar1[] = {45,2, 4, 34, 23};
    
    int i, j;
    int temp;
    
    for(i = 0; i < NUM - 1; i++)
    {
        for(j = i + 1; j < NUM; j++)
        {
            if(ar1[i] > ar1[j])
            {
                temp = ar1[i];
                ar1[i] = ar1[j];
                ar1[j] = temp;
            }
        }
    }
    
    for(i = 0; i < NUM; i++)
    {
        printf("ar[%d]: %d
", i + 1, ar1[i]);
    }
    
    return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define NUM 15

int main(void)
{
    int i;
    
    int max;
    int ar1[NUM];
    
    printf("please input max: "); scanf("%d", &max);
    
    srand((unsigned int) time(0));
    for(i = 0; i < NUM; i++)
    {
        ar1[i] = rand() % max + 1;
        printf("%3dst: %d
", i + 1, ar1[i]);
    }
    
    int j, temp;
    
    for(i = 0; i < NUM - 1; i++)
    {
        for(j = i + 1; j < NUM; j++)
        {
            if(ar1[i] < ar1[j])
            {
                temp = ar1[i];
                ar1[i] = ar1[j];
                ar1[j] = temp;
            }
        }
    }
    puts("
============================
");
    for(i = 0; i < NUM; i++)
    {
        printf("ar1[%d]: %d
", i, ar1[i]);
    }
    
    return 0;
} 

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define SIZE 10

void sort(int ar1[], int n);

int main(void)
{
    int i;
    int data[SIZE];
    
    srand((unsigned int) time(0));
    
    for(i = 0; i < SIZE; i++)
    {
        data[i] = rand() % 10 + 1;
    }
    
    printf("the original data is: 
");
    for(i = 0; i < SIZE; i++)
    {
        printf("%4d
", data[i]);
    }
    printf("
");
    
    puts("
==============================
");
    sort(data, SIZE);
    for(i = 0; i < SIZE; i++)
    {
        printf("%4d
", data[i]);
    }
    
    return 0;
}

void sort(int ar1[], int n)
{
    int i, j;
    int temp;
    for(i = 0; i < n - 1; i++)
    {
        for(j = i + 1; j < n; j++)
        {
            if(ar1[i] < ar1[j])
            {
                temp = ar1[i];
                ar1[i] = ar1[j];
                ar1[j] = temp;
            }
        }
    }
}

6、

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define SIZE 10

int main(void)
{
    int i, j;
    int data[10] = {0};

    srand((unsigned int) time(0));
    
    for(i = 0; i < SIZE; i++)
    {
        int temp;
        temp = rand() % 10 + 1;
        printf("temp: %d
", temp);
        for(j = 0; j < 10; j++)
        {
            if(temp == j + 1)
            {
                data[j] += 1;
            }
        }
    }
    puts("
counts:
");
    for(i = 0; i < 10; i++)
    {
        printf("%d: %d
", i + 1, data[i]);
    }
    
    return 0;
} 

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define SIZE 100

int main(void)
{
    int i, j;
    int data[10] = {0};

    srand((unsigned int) time(0));
    
    for(i = 0; i < SIZE; i++)
    {
        int temp;
        temp = rand() % 10 + 1;
        //printf("temp: %d
", temp);
        for(j = 0; j < 10; j++)
        {
            if(temp == j + 1)
            {
                data[j] += 1;
            }
        }
    }
    puts("
counts:
");
    for(i = 0; i < 10; i++)
    {
        printf("%d: %d
", i + 1, data[i]);
    }
    
    return 0;
} 

 

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define SIZE 11
#define LEN 1000

int main(void)
{
    int i, j;
        
    for(i = 1; i < SIZE; i++)
    {
        printf("%dst loop!
", i);
        srand(i);
        
        int data[SIZE] = {0};
        
        for(j = 0; j < LEN; j++)
        {
            int temp;
            temp = rand() % 10 + 1;
            data[temp]++;
        }
        for(j = 1; j < SIZE; j++)
        {
            printf("%d: %d
", j, data[j]);
        }
        printf("
");
    }
    
    return 0;
}

7、

[root@centos79 test2]# cat diceroll.c
#include "diceroll.h"
#include <stdio.h>
#include <stdlib.h>


static int rollem(int sides)
{
        int roll;

        roll = rand() % sides + 1;

        return roll;
}

int roll_n_dice(int dice, int sides)
{
        int d;
        int total = 0;
        if(sides < 2)
        {
                printf("need at least 2 sides.
");
                return -2;
        }

        if(dice < 1)
        {
                printf("need at least 1 die.
");
                return -1;
        }

        for(d = 0; d < dice; d++)
        {
                total += rollem(sides);
        }
        return total;
}

[root@centos79 test2]# cat diceroll.h
int roll_n_dice(int dice, int sides);

[root@centos79 test2]# cat manydice.c
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include "diceroll.h"

int main(void)
{
        int dice, roll;
        int sides;
        int status;
        printf("enter the number of sets, enter q to stop: ");
        int loop;

        while(scanf("%d", &loop) == 1 && loop >= 1)
        {
                printf("how many sides and how many dice? ");
                if(scanf("%d", &sides) == 1 && sides > 0 && scanf("%d", &dice) == 1)
                {
                        int i;
                        for(i = 1; i <= loop ; i++)
                        {
                                srand(i * (unsigned int) time(0));
                                roll = roll_n_dice(dice, sides);
                                if(i == 1)
                                {
                                        printf("here are %d sets of %d %d-sides throws.
", loop, dice, sides);
                                }
                                printf("%d ", roll);
                                if(i % 15 == 0 || i == loop)
                                {
                                        putchar('
');
                                }
                        }
                        while(getchar() != '
')
                                continue;
                }
                else
                {
                        printf("the sides should be positive integer, dice should be positive integer.
");
                        printf("try again?");
                }
                printf("how many sets? enter q to stop：");
        }

}

[root@centos79 test2]# ls
diceroll.c  diceroll.h  manydice.c
[root@centos79 test2]# gcc *
[root@centos79 test2]# ls
a.out  diceroll.c  diceroll.h  diceroll.h.gch  manydice.c

[root@centos79 test2]# ./a.out
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-sides throws.
9 4 8 16 3 10 13 12 9 6 6 12 9 14 8
12 11 13
how many sets? enter q to stop：18
how many sides and how many dice? 6 3
here are 18 sets of 3 6-sides throws.
10 7 5 9 15 8 11 11 17 8 15 16 10 10 11
14 13 10
how many sets? enter q to stop：46
how many sides and how many dice? 6 3
here are 46 sets of 3 6-sides throws.
11 7 14 13 11 9 13 10 13 13 11 12 8 11 13
7 6 11 7 13 9 10 18 7 9 4 17 12 10 10
10 13 8 16 11 11 6 8 13 9 17 8 16 11 7
12
how many sets? enter q to stop：q

[root@centos79 test]# cat diceroll.c
#include "diceroll.h"
#include <stdio.h>
#include <stdlib.h>

int roll_count = 0;

static int rollem(int sides)
{
        int roll;
        roll = rand() % sides + 1;
        ++roll_count;
        return roll;
}

int roll_n_dice(int dice, int sides)
{
        int d;
        int total = 0;
        if(sides < 2)
        {
                printf("need at lease 2 sides.
");
                return -2;
        }

        if(dice < 1)
        {
                printf("need at least 1 die.
");
                return -1;
        }
        for(d = 0; d < dice; d++)
        {
                total += rollem(sides);
        }
        return total;
}

[root@centos79 test]# cat *.h
extern int roll_count;
int roll_n_dice(int dice, int sides);

[root@centos79 test]# cat manydice.c
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include "diceroll.h"

int main(void)
{
        int dice, roll;
        int sides;
        int set;
        srand((unsigned int) time(0));
        printf("enter the number of sets; enter q to stop: ");
        while(scanf("%d", &set) == 1 && set > 0)
        {
                printf("how  many sides and how many sice? ");
                if(scanf("%d %d", &sides, &dice) == 2 && sides > 0 && dice > 0)
                {
                        printf("here are %d sets of %d %d-sided throws.
", set, dice, sides);
                        int i;
                        for(i = 1; i <= set; i++)
                        {
                                roll = roll_n_dice(dice, sides);
                                printf(" %d", roll);
                        }
                        set = 0;
                        putchar('
');
                }
                printf("enter the number of sets; enter q to stop: ");
        }
        printf("count:  %d
", roll_count);

        return 0;
}

[root@centos79 test]# ls
diceroll.c  diceroll.h  manydice.c
[root@centos79 test]# gcc *
[root@centos79 test]# ls
a.out  diceroll.c  diceroll.h  diceroll.h.gch  manydice.c

[root@centos79 test]# ./a.out
enter the number of sets; enter q to stop: 18
how  many sides and how many sice? 6 3
here are 18 sets of 3 6-sided throws.
 13 15 7 7 11 16 11 14 10 9 11 12 12 8 10 10 7 13
enter the number of sets; enter q to stop: 5
how  many sides and how many sice? 6 3
here are 5 sets of 3 6-sided throws.
 14 11 8 8 9
enter the number of sets; enter q to stop: q
count:  69

8、

#include <stdio.h>
#include <stdlib.h>

int * make_array(int num, int val);
void show_array(const ar[], int num);

int main(void)
{
    int * pa;
    int size;
    int value;
    
    printf("enter the size: ");
    while(scanf("%d", &size) == 1 && size > 0)
    {
        printf("input value: "); scanf("%d", &value);
        pa = make_array(size, value);
        if(pa)
        {
            show_array(pa, size);
            free(pa);
        }
        printf("input the size:(< 0 to quit)  ");
    }
    return 0;
}

int * make_array(int num, int val)
{
    int * temp = (int *) malloc(num * sizeof(int));
    if(temp == NULL)
    {
        return NULL;
    }
    int i;
    for(i = 0; i < num; i++)
    {
        temp[i] = val;
    }
    return temp;
}

void show_array(const ar[], int num)
{
    int i;
    for(i = 0; i < num; i++)
    {
        printf("%d ", ar[i]);
        if((i + 1) % 8 == 0)
        {
            putchar('
');
        }
    }
    putchar('
');
}

9、

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(void)
{
    int amount;
    printf("how may words do you wish to enter? ");
    scanf("%d", &amount);
    printf("enter %d words now: 
", amount);
    char **pst = (char **) malloc(amount * sizeof(char *));
    
    int i;
    for(i = 0; i < amount; i++)
    {
        char temp[100];
        scanf("%s", temp);
        int length = strlen(temp);
        char * str = (char *) malloc (length * sizeof(char));
        
        strcpy(str, temp);
        *(pst + i) = str;
    }
    
    puts("
=================
");
    for(i = 0; i < amount; i++)
    {
        printf("%s
", *(pst + i));
    }
    free(pst);
    printf("
all done!
");
    
    return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(void)
{
    int num;
    printf("how many words: ");
    scanf("%d", &num);
    
    printf("enter %d num now: 
", num);
    
    char **pst = (char **) malloc(num * sizeof(char *));
    
    int i;
    for(i = 0; i < num; i++)
    {
        char temp[100];
        scanf("%s", temp);
        int length;
        length = strlen(temp);
        char *str = (char *) malloc(length * sizeof(char));
        
        strcpy(str, temp);
        *(pst + i) = str;
    }    
    
    puts("

");
    for(i = 0; i < num; i++)
    {
        printf("%s
", *(pst + i));
    }
    free(pst);

    return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(void)
{
    int num;
    int i;
    
    printf("please input the num: ");
    scanf("%d", &num);
    
    char ** ptd = (char **) malloc(num * sizeof(char *));
    
    printf("now input the words:
");
    
    for(i = 0; i < num; i++)
    {
        char temp[44];
        scanf("%s", temp);
        int length;
        length = strlen(temp);
        char * str = (char *) malloc(length * sizeof(char));
        
        strcpy(str, temp);
        *(ptd + i) = str;
    }
    
    printf("now show the result: 
");
    for(i = 0; i < num; i++)
    {
        printf("%s
", ptd[i]);
    }
    free(ptd);
    
    return 0;
}