实验六的作业

test 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;
            
}

 

test 1-2；

#include <stdio.h>
#define N 4
int main()
{
    char x[N]={'1','9','8','4',};
    int i;
    char *p;
    
    for(i=0;i<N;++i)
       printf("%c",x[i]);
       printf("\n");
       
    for(p=x;p<x+N;++p)
       printf("%c",*p);
       printf("\n");
       
       p=x;
       for(i=0;i<N;++i)
       printf("%c",*(p+i));
       printf("\n");
       
       p=x;
       for(i=0;i<N;++i)
       printf("%c",p[i]);
       printf("\n");
    
        return 0;
            
}

 

test 2-1；

#include <stdio.h>

int main()
{
    int x[2][4]={{1,9,8,4},{2,0,2,2}};
    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; 
}

 

test2-2；

#include <stdio.h>

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

 

test 3-1；

#include <stdio.h> 
#include <string.h>
#define N 80

int main()
{
    char s1[]="C,I love u.";
    char s2[]="C,I hate u.";
    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("\n before swap:\n");
    printf("s1:%s\n",s1);
    printf("s2:%s\n",s2);
    
    printf("\n swapping...\n");
    strcpy(tmp,s1);
    strcpy(s1,s2);
    strcpy(s2,tmp);
    
    printf("\n after swap:\n") ;
    printf("s1:%s\n",s1);
    printf("s1:%s\n",s2);
    
    return 0;
    
}

 

test3-2；

#include <stdio.h> 
#include <string.h>
#define N 80

int main()
{
    char *s1="C,I love u.";
    char *s2="C,I hate u.";
    char *tmp;
    
    printf("sizeof(s1) vs.strlen(s1):\n");
    printf("sizeof(s1)= %d\n",sizeof(s1));
    printf("strlen(s1)= %d\n",strlen(s1));
    
    printf("\n before swap:\n");
    printf("s1:%s\n",s1);
    printf("s2:%s\n",s2);
    
    printf("\n swapping...\n");
    tmp=s1;
    s1=s2;
    s2=tmp;
    
    printf("\n after swap:\n") ;
    printf("s1:%s\n",s1);
    printf("s1:%s\n",s2);
    
    return 0;
    
    return 0;
    
}

 

test4

#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;
}
int check_id(char *str)
{
    int i;
     for(i=0;str[i]!='\0';++i)
     {
             if((strlen(str)==18)&&(str[i]>='0'&&str[i]<='9')||str[i]=='X')
             return 1;
             else 
            break;
        
        
     }
    
    return 0;    
    
}

 

test5；

#include <stdio.h>
#include <string.h>
#define N 80
int is_palindrome(char *s); // 函数声明
int main()
{
  char str[N];
  int flag;
  printf("Enter a string:\n");
  gets(str);
  flag = is_palindrome(str); // 函数调用
   if (flag)
     printf("YES\n");
   else
     printf("NO\n");
  return 0;
}
// 函数定义
int is_palindrome(char *s)
{
    int i,n=strlen(s);
    for(i=0;s[i]!=0;i++)
    {
        if(s[i]==s[n-i-1])
        return 1;
        else 
        break;
    }
        return 0;
}

 

test6 ；

#include <stdio.h>
#define N 80
void encoder(char *s); // 函数声明
void decoder(char *s); // 函数声明
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); // 函数调用
   printf("%s\n", words);
   printf("对编码后的英文文本解码: ");
   decoder(words); // 函数调用
   printf("%s\n", words);
   
   return 0;
}
void encoder(char *s)
{
    int i;
    for(i=0;s[i]!=0;++i)
    {
        if((s[i]>='a'&&s[i]<='z')||(s[i]>='A'&&s[i]<='Z'))
        s[i]=s[i]+1; 
        if(s[i]=='Z')
        s[i]='A';
        else if(s[i]=='z')
        s[i]='a';
    }
}
void decoder(char *s)
{
    int i;
    for(i=0;s[i]!=0;++i)
    {
        if((s[i]>='a'&&s[i]<='z')||(s[i]>='A'&&s[i]<='Z'))
        s[i]=s[i]-1; 
        if(s[i]=='A')
        s[i]='Z';
        else if(s[i]=='a')
        s[i]='z';
    }
}