李湘楠实验五实验报告

//5.4test1_1.c
#include <stdio.h>
#define N 4

int main()
{   
    int x[N] = {1,9,8,4};
    int i;
    int *p;

    //方式1：通过数组名和下标遍历输出数组元素
    for (i = 0;i < N; ++i)
        printf("%d",x[i]);
    printf("\n");

    //方式2：通过指针变量遍历输出数组元素（写法1）
    for (p = x;p < x + N;++p)
        printf("%d",*p);
    printf("\n");

    //方式2：通过指针变量遍历输出数组元素（写法2）
    p = x;
    for (i = 0;i < N;++i)
        printf("%d",*(p + i));
    printf("\n");

    //方式2：通过指针变量遍历输出数组元素（写法3）
    p = x;
    for (i = 0;i < N;++i)
        printf("%d",p[i]);
    printf("\n");

    return 0;
}

//5.4test1_2.c
#include <stdio.h>

int main()
{
    int x[2][4] = {{1,9,8,4},{2,0,4,9}};
    int i,j;
    int *p;  //指针变量，存放int类型数据的地址
    int(*q)[4];//指针变量，指向包含4个int型元素的一组数据
    
    //使用数组名、下标访问二维数组元素
    for (i = 0;i < 2;++i)
    {
        for (j = 0;j < 4;++j)
            printf("%d",x[i][j]);
        printf("\n");
    }

    //使用指针变量p间接访问二维数组元素
    for (p = &x[0][0],i = 0;p < &x[0][0] + 8;++p,++i)
    {
        printf("%d",*p);
        if((i + 1)%4 == 0)
            printf("\n");
    }
    //使用指针变量q间接访问二维数组元素
    for (p = &x[0][0],i = 0;p < &x[0][0] + 8;++p,++i)
    {
        for (j = 0;j < 4;++j)
            printf("%d",*(*q + j));
        printf("\n");
    }

    return 0;
}

//5.4test2_1.c
#include <stdio.h>
#include <string.h>
#define N 80

int main()
{
   char s1[] = "Learning makes me happy";
   char s2[] = "Learning makes me sleepy";
   char tmp[N];

   printf("sizeof(s1) vs. strlen(s1): \n");
   printf("sizeof(s1) = %d\n", sizeof(s1));
   printf("strlen(s1) = %d\n", strlen(s1));

   printf("\nbefore swap: \n");
   printf("s1: %s\n", s1);
   printf("s2: %s\n", s2);

   printf("\nswapping...\n");
   strcpy(tmp, s1);
   strcpy(s1, s2);
   strcpy(s2, tmp);

   printf("\nafter swap: \n");
   printf("s1: %s\n", s1);
   printf("s2: %s\n", s2);

   return 0;
}

1、24个字节；sizeof(s1)计算的是数组s1的大小，strlen统计的是字符串的长度

2、不能。因为s1是指针变量，储存地址而非字符串

3、是

//5.4test2_2.c
#include <stdio.h>
#include <string.h>
#define N 80

int main()
{
    char *s1 = "Learning makes me happy";
    char *s2 = "Learning makes me sleepy";
    char *tmp;

    printf("sizeof(s1) vs. strlen(s1): \n");
    printf("sizeof(s1) = %d\n", sizeof(s1));
    printf("strlen(s1) = %d\n", strlen(s1));

    printf("\nbefore swap: \n");
    printf("s1: %s\n", s1);
    printf("s2: %s\n", s2);

    printf("\nswapping...\n");
    tmp = s1;
    s1 = s2;
    s2 = tmp;

    printf("\nafter swap: \n");
    printf("s1: %s\n", s1);
    printf("s2: %s\n", s2);

    return 0;
}

1、s1存放的是数组首元素的地址，sizeof(s1)计算的是s1的长度，strlen(s1)统计的是其所包含的字符串的长度。

2、能。task2_1中调用的是指针（地址），task2_2中调用的是数组内容

3、交换的是各自的地址；没有交换。

//5.4test3.c
#include <stdio.h>

void str_cpy(char *target, const char *source);
void str_cat(char *str1, char *str2);

int main()
{
    char s1[80], s2[20] = "1984";

    str_cpy(s1, s2);
    puts(s1);

    str_cat(s1, " Animal Farm");
    puts(s1);

    return 0;
}
void str_cpy(char *target, const char *source)
{
    while (*target++ = *source++)
       ;
}

void str_cat(char *str1, char *str2)
{
    while (*str1)
       str1++;

    while (*str1++ = *str2++)
       ;
}

//5.4test4.c
#include <stdio.h>
#define N 80
int func(char *);

int main()
{
    char str[80];

    while (gets(str) != NULL)
    {
         if (func(str))
            printf("yes\n");
         else
            printf("no\n");
    }

    return 0;
}

int func(char *str)
{
    char *begin, *end;

    begin = end = str;

    while (*end)
        end++;
    end--;

    while (begin < end)
    {
        if (*begin != *end)
           return 0;
        else
        {
           begin++;
           end--;
        }
    }

    return 1;
}

//5.4test5.c
#include <stdio.h>
#define N 80

void func(char *);

int main()
{
    char s[N];

    while (scanf("%s", s) != EOF)
    {
        func(s);
        puts(s);
    }

    return 0;
}

void func(char *str)
{
    int i;
    char *p1, *p2, *p;

    p1 = str;
    while (*p1 == '*')
       p1++;

    p2 = str;
    while (*p2)
      p2++;
    p2--;

    while (*p2 == '*')
      p2--;

    p = str;
    i = 0;
    while (p < p1)
    {
      str[i] = *p;
      p++;
      i++;
    }

    while (p <= p2)
    {
      if (*p != '*')
      {
         str[i] = *p;
         i++;
      }
      p++;
    }

    while (*p != '\0')
    {
        str[i] = *p;
        p++;
        i++;
    }

    str[i] = '\0';
}

//5.4test6_1.c
#include <stdio.h>
#include <string.h>
void sort(char *name[], int n);

int main()
{
    char *course[4] = {"C Program",
                       "C++ Object Oriented Program",
                       "Operating System",
                       "Data Structure and Algorithms"};
    int i;

    sort(course, 4);

    for (i = 0; i < 4; i++)
         printf("%s\n", course[i]);

    return 0;
}

void sort(char *name[], int n)
{
    int i, j;
    char *tmp;

    for (i = 0; i < n - 1; ++i)
        for (j = 0; j < n - 1 - i; ++j)
            if (strcmp(name[j], name[j + 1]) > 0)
            {
                tmp = name[j];
                name[j] = name[j + 1];
                name[j + 1] = tmp;
            }
}

//5.4test6_2.c
#include <stdio.h>
#include <string.h>
void sort(char *name[], int n);

int main()
{
    char *course[4] = {"C Program",
                       "C++ Object Oriented Program",
                       "Operating System",
                       "Data Structure and Algorithms"};
    int i;

    sort(course, 4);
    for (i = 0; i < 4; i++)
        printf("%s\n", course[i]);

    return 0;
}

void sort(char *name[], int n)
{
    int i, j, k;
    char *tmp;

    for (i = 0; i < n - 1; i++)
    { 
        k = i;
        for (j = i + 1; j < n; j++)
            if (strcmp(name[j], name[k]) < 0)
                k = j;

        if (k != i)
        {
            tmp = name[i];
            name[i] = name[k];
            name[k] = tmp;
        }
    }
}

交换的是指针变量的值

//5.4test7.c
#include <stdio.h>
#include <string.h>
#define N 5

int check_id(char *str); // 函数声明

int main()
{
    char *pid[N] = {"31010120000721656X",
                    "330106199609203301",
                    "53010220051126571",
                    "510104199211197977",
                    "53010220051126133Y"};
    int i;

    for (i = 0; i < N; ++i)
        if (check_id(pid[i])) // 函数调用
            printf("%s\tTrue\n", pid[i]);
        else
            printf("%s\tFalse\n", pid[i]);

    return 0;
}

// 函数定义
// 功能: 检查指针str指向的身份证号码串形式上是否合法。
// 形式合法，返回1，否则，返回0
int check_id(char *str)
{
// 补足函数实现
    int cnt=0;
    while(*str){
        if((*str>='0'&&*str<='9')||*str=='X'){
            str++;
            cnt++;
        }
        else{
            return 0;
        }
    }
    if(cnt!=18) return 0;
    return 1;
}

//5.4test8.c

#include <stdio.h>
#include <string.h>
#define N 80
void encoder(char *s); 
void decoder(char *s); 
int main()
{
char words[N];
printf("输入英文文本: ");
gets(words);
printf("编码后的英文文本: ");
encoder(words); 
printf("%s\n", words);
printf("对编码后的英文文本解码: ");
decoder(words); 
printf("%s\n", words);
return 0;
}

void encoder(char *s)
{
    while(*s){
        if(*s >= 'a' && *s <= 'y' || *s >= 'A' && *s <= 'Y'){
            *s += 1;
            s++;
            continue; 
        }
        else if(*s == 'z' || *s == 'Z'){
            *s -= 25;
            s++;
            continue;
        }
        s++;
    }
}

void decoder(char *s)
{
    while(*s){
        if(*s >= 'b' && *s <= 'z' || *s >= 'B' && *s <= 'Z'){
            *s -= 1;
            s++;
            continue;
        }
        else if(*s == 'a' || *s == 'A'){
            *s += 25;
            s++;
            continue;
        }
        s++;
    }


}

posted @ 2023-05-11 15:30 lenmoye 阅读(12) 评论(0) 收藏举报

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