实验五

#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");
    for(i=0;i<N;i++){
        printf("%d",p[i]);
    }   printf("\n");
    
    
    return 0;
} 


#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(*end!=*begin)
            return 0;
        else{
            begin++;
            end--;
        }
    }
    return 1; 
}







#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;
    
    
}



#include <stdio.h>
#include <string.h>
#define N 80
int main()
{
char *s1 = "Learning makes me happy";
char *s2 = "Learning makes me sleepy";
char *tem;
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");
tem=s1;    //指针直接用
s1=s2;
s2=tem;
printf("\nafter swap: \n");
printf("s1: %s\n", s1);
printf("s2: %s\n", s2);
return 0;
}


#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++)
    ;
}



#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=0;
    char *p1,*p2,*p;
    p=p1=p2=str;
    while(*p1=='*')
       p1++;
    while(*p2)
       p2++;
    p2--;
    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';
    
}




#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];       //交换地址 
              name[j]=name[j+1];
              name[j+1]=tmp;
          }
      }
    }
}





#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){
    
      for(j=0;j<n-1-i;++j){
          k=i;
          for(j=i+1;j<n;j++)
            {  if(strcmp(name[j],name[k])<0)
            k=j;
             } 
          
                //选择排序 
          
          if(k!=i){
              tmp=name[i];       
              name[i]=name[k];
              name[k]=tmp;
          }
      }
    }
}



#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(*(str+18)!='\0'||*(str+17)=='\0')
        return 0; 
        int i=0;
         while((*(str+i)>='0'&&*(str+i)<='9')||*(str+i)=='X') 
                i++;    
    if(i==18)
      return 1;
    else
      return 0;
}



#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;
}

/*函数定义
功能：对s指向的字符串进行编码处理
编码规则：
对于a~z或A~Z之间的字母字符，用其后的字符替换; 其中，z用a替换，Z用A替换
其它非字母字符，保持不变
*/
void encoder(char *s)
{
    while(*s){
    
   if((*s>='a'&&*s<'z')||(*s>='A'&&*s<'Z'))
        *s=*s+1;
    else if(*s=='z')
        *s='a';
    else if(*s=='Z')
        *s='A';
    s++;}
}

/*函数定义
功能：对s指向的字符串进行解码处理
解码规则：
对于a~z或A~Z之间的字母字符，用其前面的字符替换; 其中，a用z替换，A用Z替换
其它非字母字符，保持不变
*/
void decoder(char *s)
{
   while(*s){
    
   if((*s>'a'&&*s<='z')||(*s>'A'&&*s<='Z'))
        *s=*s-1;
    else if(*s=='a')
        *s='z';
    else if(*s=='A')
        *s='Z';
    s++;}
}