c语言小白的学习之路
时隔一个月，在学习c语言的漫漫长路上有前进了一小步
以下代码如有错误或建议，敬请斧正
12-1.
// 12-1 改写12.4.c
#include <stdio.h>
int cirtic(void);
int main(void)
{
int units;
printf("How many pounds to firkin of butter?\n");
scanf("%d", &units);
while (units != 56)
units = cirtic();
printf("You must have look it up!");
return 0;
}
int cirtic(void)
{
int units;
printf("No luck, my friends. Try again\n");
scanf("%d",&units);
return units;
}
12-2.
pe12 --2a.c
//pe12 --2a.c
#include <stdio.h>
#include "pe12-2a.h"
void set_mode(int n_mode)
{
if (n_mode != 1 && n_mode != 0)
{
if (s_mode == 1)
printf("Invalid mode specified, Mode 1(US) used.\n");
else if (s_mode == 0)
printf("Invalid mode specified, Mode 0(METRIC) used.\n");
}
else
s_mode = n_mode;
}
void get_info(void)
{
printf("Enter distance traveled in kilomteres: ");
scanf("%f",&distance);
printf("Enter fuel consumed in gallons: ");
scanf("%f",&fuel);
}
void show_info(void)
{
if (s_mode == 0)
printf("Fuel consumption is %f liters per 100 km\n",fuel/distance*100);
else if (s_mode == 1)
printf("Fuel consumption is %f miles per gallon.\n",distance/fuel);
}
pe2a-2a.h
//pe2a-2a.h
void set_mode(int);
void get_info(void);
void show_info(void);
static int s_mode;
static float fuel;
static float distance;
12-3.
pe12-3a.c
// pe12-3a.c
#include <stdio.h>
#include "pe12-3a.h"
int set_mode(int new_mode,int last_mode)
{
if (new_mode != 1 && new_mode != 0)
{
if (last_mode == 1)
printf("Invalid mode specified, Mode 1(US) used.\n");
else if (last_mode == 0)
printf("Invalid mode specified, Mode 0(METRIC) used.\n");
return last_mode;
}
else
return new_mode;
}
float get_info_distance(int mode,float distance)
{
if (mode == 0)
printf("Enter distance traveled in kilomteres: ");
else if (mode == 1)
printf("Enter distance traveled in miles: ");
scanf("%f",&distance);
return distance;
}
float get_info_fuel(int mode,float fuel)
{
if (mode == 0)
printf("Enter fuel consumed in liters: ");
else if (mode == 1)
printf("Enter fuel consumed in gallons: ");
scanf("%f",&fuel);
return fuel;
}
void show_info(int mode,float distance,float fuel)
{
if (mode == 0)
printf("Fuel consumption is %f liters per 100 km\n",fuel/distance*100);
else if (mode == 1)
printf("Fuel consumption is %f miles per gallon.\n",distance/fuel);
}
pe12-3a.h
//pe12-3a.h
int set_mode(int,int);
float get_info_distance(int,float);
float get_info_fuel(int,float);
void show_info(int,float,float);
pe12-3b.h
// pe12-3b.c
// 与pe12-3a.c 一起编译
#include <stdio.h>
#include "pe12-3a.h"
int main(void)
{
int mode; // mode = 方式
int last_mode = 0;
float distance;
float fuel;
printf("Enter 0 for metric(公制的) mode, 1 for US mode: ");
scanf("%d",&mode);
while(mode >= 0)
{
mode = set_mode(mode,last_mode);
last_mode = mode;
distance = get_info_distance(mode,distance);
fuel = get_info_fuel(mode,fuel);
show_info(mode,distance,fuel);
printf("Enter 0 for metric(公制的) mode, 1 for US mode: ");
printf(" (-1 to quit): ");
scanf("%d",&mode);
}
printf("Done!");
return 0;
}
12-4
// 12-4
#include <stdio.h>
static int count;
int re_ct(void);
int main(void)
{
int n = 5 // n可变;
int i = 1;
for (; i <= n; i++)
{
count = re_ct();
}
printf("%d",count);
}
int re_ct(void)
{
return ++count;
}
12-5
// 12-5
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define MAX_NUMBER 100
static int array[MAX_NUMBER];
void rank(int *); //排序
void turn(int *,int,int); //交换位置
int main(void)
{
int i = 0;
int number[MAX_NUMBER];
srand((unsigned int) time(0));
for (; i < MAX_NUMBER; i++)
{
array[i] = rand() % 10 + 1;
}
rank(array);
for (i = 0; i < MAX_NUMBER; i++)
{
if (array[i] != array[i-1] && i != 0)
putchar('\n');
printf("%d ",array[i]);
}
return 0;
}
void rank(int *random)
{
int i,j;
int MAX_mark; // 记录最大值在原数组的位置
int max;
for (i = 0; i < MAX_NUMBER;i++)
{
for (j = i,max = random[j],MAX_mark = j; j < MAX_NUMBER; j++)
{
if (max < random[j])
{
max = random[j];
MAX_mark = j;
}
}
turn(random,i,MAX_mark);
}
}
void turn(int *random,int i,int MAX_mark)
{
int temp;
temp = random[i];
random[i] = random[MAX_mark];
random[MAX_mark] = temp;
}
12-6
// 12-6
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int main(void)
{
int array[1000];
int i = 0;
int number[10];
for (i = 0 ;i < 10; i++)
number[i] = 0;
srand((unsigned int) 1);
for (i = 0;i < 1000; i++)
{
array[i] = rand() % 10 + 1;
switch (array[i])
{
case 1:
number[0]++;break;
case 2:
number[1]++;break;
case 3:
number[2]++;break;
case 4:
number[3]++;break;
case 5:
number[4]++;break;
case 6:
number[5]++;break;
case 7:
number[6]++;break;
case 8:
number[7]++;break;
case 9:
number[8]++;break;
case 10:
number[9]++;break;
}
}
printf("1 2 3 4 5 6 7 8 9 10\n");
for (i = 0; i < 10 ;i++)
{
printf("%-4d",number[i]);
}
return 0;
}
12-7
略
12-8
//pe12-8.c
#include <stdio.h>
#include <stdlib.h>
int *make_array(int elem, int val);
void show_array(const int ar[], int n);
int main(void)
{
int *pa;
int size;
int value;
printf("Enter the number if elements: ");
while (scanf("%d", &size) == 1 && size > 0)
{
printf("Enter the initialization value: ");
scanf("%d", &value);
pa = make_array(size, value);
if (pa)
{
show_array(pa, size);
free(pa);
}
printf("Enter the number of elements (<1 to quit): ");
}
printf("Done!");
return 0;
}
int *make_array(int elem, int val)
{
int *pd;
int i = 0;
pd = (int *)malloc(elem * sizeof(int));
for (;i < elem; i++)
pd[i] = val;
return pd;
}
void show_array(const int ar[], int n)
{
int i;
for (i = 0;i < n; i++)
{
printf("%-5d",ar[i]);
if (i % 7 == 0 && i != 0)
putchar('\n');
}
printf("\n");
}
12-9
#include <stdio.h>
#include <stdlib.h>
int main(void)
{
char **ptr;
int n;
int count;
char arr[20];
int i,j;
printf("How many words do you wish to enter? ");
scanf("%d",&n);
getchar();
ptr = (char **) malloc (n * sizeof(char *));
printf("Enter %d words now: ",n);
for (i = 0; i < n; i++)
{
while ((arr[count] = getchar()) != ' ' && arr[count] != '\n')
count++;
ptr[i] = (char *)malloc (count * sizeof(char));
for (j = 0; j < count; j++)
{
ptr[i][j] = arr[j];
printf("%c",ptr[i][j]);
}
printf("\n");
count = 0;
}
// 此处省略free()函数,其实是忘记加了........
return 0;
}
总结：
- 排序中重置变量，很关键。
- 有关malloc的语法格式，12-9 中 的指向一个指向char类型指针的写法,百度和得知*(char **) malloc (n * sizeof(char *));*用于该表达.
- 随机数，time（0）作为种子时在循环内生成的数在一秒内使用同一个种子，故生成数相同。
欢迎留言，共同进步.