实验5

实验任务1:

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;
}

1.2

#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型元素的一维数组
    int(*q)[4];//指针变量,指向包含4个int型元素的一维数组
    
    //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(q = x;q<x+2;++q)
    {
        for(j = 0;j<4;++j)
            printf("%d",*(*q+j));
        printf("\n");
     } 
     
     return 0;
}

实验任务2:

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("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(s2,s1);
    strcpy(s2,tmp);
    
    printf("\nafter swap: \n");
    printf("s1: %s\n",s1);
    printf("s2: %s\n",s2);
    
    return 0;
}

1.数组s1大小是24,size(s1)计算地是s1在储存空间中占用的字节数,strlen统计的是s1中除空字符以外的字符个数。

2.不能,s1为字符数组名,用赋值号不能直接给字符串赋值,需要应用strcpy函数。

3.没有发生互换,只是让s2变成了s1。

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("strlen(s1) = %d\n",strlen(s1));
    
    printf("\nbefore swap: \n");
    printf("s1: %s\n",s1);
    printf("s2: %s\n",s2);
    
    printf("\swapping...\n");
    tmp = s1;
    s1 = s2;
    s2 = tmp;
    
    printf("\after swap: \n");
    printf("s1: %s\n",s1);
    printf("s2: %s\n",s2);
    
    return 0; 
 } 

1.s1中存放的是字符串第一个元素的地址 sizeof(s1)计算的是Learning所占的字节数,strlen(s1)统计的数字符串中非空字符的个数。

2.可以,因为s1为指针变量,可以使用赋值号,将字符串第一个元素的地址赋给指针变量。2.1中的s1为字符数组名,不能用赋值号。

3.交换了指针所指字符串,储存单元并没有变。

实验任务3:

#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++)
         ;
 }

实验任务4:

#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;
}

实验任务5:

#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';
}

实验任务6:

#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 Algorothms"};
    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;
            }
}

6.2:

#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。

实验任务7:

 

#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)
{
    if(strlen(str)!=18)
        return 0;
    else
    {
        char *p;
        p=str;
        while(*p>='0'&&*p<='9'||*p=='X')
            p++;
        if(*p=='\0')
            return 1;
        else
            return 0;
    }
}

实验任务8:

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

    system("pause");
    return 0;
}

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

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

 

posted @ 2023-05-07 15:46  都行吧  阅读(24)  评论(0编辑  收藏  举报