# 实验5

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;
}

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。

#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
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;
}

#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';
}

#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;
}
}
}

#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;
}
}

#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(22)  评论(0编辑  收藏  举报