实验五

任务一

task 1.1

#include <stdio.h>
#define N 4

int main()
{
    int x[N] = {1,9,8,4};
    int i;
    int *p;
    
    for (i=0; i<N; ++i)
        printf("%d", x[i]);
    printf("\n");
    
    for(p=x;p<x+N;++p)
       printf("%d", *p);
    printf("\n");
    
    p=x;
    for(i=0;i<N;++i)
       printf("%d", *(p+i));
    printf("\n");
    
    p=x;
    for(i=0;i<N;++i)
       printf("%d",p[i]);
    printf("\n");
    
    return 0;         
}

task 1.2

#include <stdio.h>

int main()
{
    int x[2][4]={{1, 9, 8, 4}, {2, 0, 4, 9}};
    int i, j;
    int *p;
    int(*q)[4];
    
    for (i = 0;i < 2; ++i)
    {
        for(j = 0; j < 4; ++j)
           printf("%d", x[i][j]);
        printf("\n");
    }
    
    for (p = &x[0][0], i = 0; p < &x[0][0] + 8; ++p, ++i)
    {
        printf("%d", *p);
        if((i+1) % 4 == 0)
        printf("\n");
    }
    
    for(q = x; q < x + 2; ++q)
    {
        for (j = 0; j < 4; ++j)
           printf("%d", *(*q + j));
        printf("\n");   
    }
    
    return 0;
}

任务二

task 2.1

#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("sizeof(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;
}

问题1：数组s1的大小为23,sizeof计算占据多少字节,带\0,strlen计算字节长度

问题2：不能，s1是一个数组

问题3：完成了交换

task 2.2

#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("sizeof(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;
}

问题一：指针变量s1中存放的是字符串的起始地址，sizeof(s1)计算的是数组所占的字节数，strlen(s1)统计的还是数组的长度
问题二：可以，指针可以指向赋予的一串字符
问题三：交换的是指针的指向，实际在储存单元中没有被交换

任务三

#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++)
    ;
}

任务四

#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;
}

任务五

#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';
    }

任务六

task 6.1

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

int main()
{
    char *course[4] = {"C Program",
                       "C++ Object Orinted 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;
            }
}

task 6.2

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

int main()
{
    char *course[4] = {"C Program",
                       "C++ Object Orinted 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[j];
                name[i] = name[k];
                name[k] = tmp;
            }
        }
}

交换的是指针变量的值

任务七

#include <stdio.h>
#include <string.h>
#define N 5

int check_id(char *str);

int main()
{
    char *pid[N] = {"31010120000721656X",
                    "330106199609203301",
                    "53010220051126571",
                    "510104199211197977",
                    "53010220051126133Y"};
    int i;
    
    for (i = 0; i < N; ++i)
        if (check_id(pid[i]))
           printf("%s\tTrue\n", pid[i]);
        else
           printf("%s\tFalse\n", pid[i]);
           
    return 0;
}
    int check_id(char *str)
{
       char *p;
       p=str;
       while(*p>='0'&&*p<='9'||*p=='X')
          p++;
       if(*p=='\0'&&strlen(str)==18)
          return 1;
        else
          return 0;
   
}

task 8

#include <stdio.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>=65&&*s<=90||*s>=97&&*s<=122){
              *s=*s+1;
              s++;continue;
       }
       else if(*s==90||*s==122){
              *s=*s-25;
              s++;continue;
       }
       s++;
}
 return;
    
}

void decoder(char *s)
{ while(*s){
       if(*s>=66&&*s<=90||*s>=98&&*s<=122){
              *s=*s-1;
              s++;continue;
       }
       else if(*s==65||*s==97){
              *s=*s+25;
              s++;continue;
       }
       s++;
}    return;
}

posted @ 2023-05-07 20:13 zk柯r 阅读(35) 评论(0) 收藏举报

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