实验六

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

}

 

 

#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;
}

 

task1-1.c  2004     task1-2.c  2001      因为两个数据类型不同，1中p是整形占四个字节，2中是字符指针占一个字节

#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;


}

 

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

 

task2-1.c  2004  2016      task2-2.c  2001 2004        数据类型不同      

#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("\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;
}

1：12   s1所占字节数   给定字符串s1的长度       2：可以    3：交换了

#include <stdio.h>
#include <string.h>
#define N 80
int main()
{
char *s1="C,I love u.";
char *s2="C,I love 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("\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：sizeof(s1)计算的是地址变量的大小；strlen(s1)统计的是s1字符数组有效长度；2：可以  3：没有

 

#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)
{
int i,flag;
for(i=0;i<=17;i++)
{
if(str[i]>='0'&&str[i]<='9')
flag=1;
else
flag=0;
}

if(str[17]=='X')
flag=1;
if(strlen(str)==18&&flag==1)
return 1;
else
return 0;
}

#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)
{
int i,flag;
for(i=0;i<=17;i++)
{
if(str[i]>='0'&&str[i]<='9')
flag=1;
else
flag=0;
}

if(str[17]=='X')
flag=1;
if(strlen(str)==18&&flag==1)
return 1;
else
return 0;
}

 

 

 

#include <stdio.h>
#include <string.h>

#define N 80
int is_palindrome(char *s);
int main()
{
char str[N];
int flag;

printf("Enter a string:\n");
gets(str);

flag = is_palindrome(str);

if(flag)
printf("YES\n");
else
printf("NO\n");

return 0;
}

int is_palindrome(char *s)
{
int i=0,j;
j=strlen(s)-1;
for(i=0;i<j;i++,j--)

if(s[i]==s[j])
return 1;
else
return 0;
}

 

 

 

 

#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)
{
int i;
for(i=0;s[i]!='\0';i++)
{
if(s[i]>='a'&&s[i]<='z')
{
if(s[i]!='z')
s[i]=s[i]+1;
else
s[i]='a';
}

if(s[i]>='A'&&s[i]<='Z')
{
if(s[i]!='Z')
s[i]=s[i]+1;
else
s[i]='A';
}
}
}
void decoder(char *s)
{
int i;
for(i=0;s[i]!='\0';i++)
{
if(s[i]>='a'&&s[i]<='z')
{
if(s[i]!='a')
s[i]=s[i]-1;
else
s[i]='z';
}
if(s[i]>='A'&&s[i]<='Z')
{
if(s[i]!='A')
s[i]=s[i]-1;
else
s[i]='Z';
}
}
}