实验五
task1
#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;
}
task1-2
#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;
}
问题：
1、数组S1的大小24，sizeof计算的是变量的大小，strlen计算的是字符串的长度
2、不能 在s1中缺少数组的大小
3、内容交换
task2-1
#include <stdio.h>
#include <string.h>
#define N 80
int main()
{
char s1[] = "Learing makes me happy";
char s2[] = "Learing 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(s1,s2);
strcpy(s2,tmp);
printf ("\nafter swap:\n");
printf("s1: %s\n",s1);
printf("s2: %s\n",s2);
return 0;
}
task2-2
#include <stdio.h>
#include <string.h>
#define N 80
int main()
{
char *s1 = "Learing makes me happy";
char *s2 = "Learing 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("\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、指针变量s1中存放的是字符串
sizeof计算的是该指针所占的地址空间
strlen统计的是字符串的长度
2、可以替换，task2-2是定义char类型的指针变量s1，在给s1赋值字符串；task2-1是定义char类型的s1数组，而没有给定数组大小
3、交换的是字符串的内容；两个字符串常量在内存储存单元中没有交换
task3
#include <stdio.h>
#include <string.h>
#define N 80
int main()
{
char *s1 = "Learing makes me happy";
char *s2 = "Learing 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("\nswapping...\n");
tmp = s1;
s1 = s2;
s2 = tmp;
printf ("\nafter swap:\n");
printf("s1: %s\n",s1);
printf("s2: %s\n",s2);
return 0;
}
task4
#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;
}
task5
#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';
}
task6-1
#include <stdio.h>
#include <string.h>
void sort(char *name[], int n);
int main(){
char *course[4] = {"Cprogram",
"c++objectorientedprogram",
"operateprogram",
"daating"};
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;
}
}
task6-2
#include <stdio.h>
#include <string.h>
void sort(char *name[], int n);
int main(){
char *course[4] = {"Cprogram",
"c++objectorientedprogram",
"operateprogram",
"daating"};
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;
}
}
}
task7
#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)
{
int i;
for(i=0;*str!='\0';str++,i++)
if(*str>'9'&&*str!='X')
return 0;
if(i<18)
return 0;
return 1;
}
task8
#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)
{
for(;*s!='\0';s++){
if('A'<=*s&&'Z'>*s)
*s=*s+1;
else if(*s=='Z')
*s=*s-25;
if('a'<=*s&&'z'>*s)
*s=*s+1;
else if(*s=='z')
*s=*s-25;
}
}
/*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)
{
for(;*s!='\0';s++){
if('A'<*s&&'Z'>=*s)
*s=*s-1;
else if(*s=='A')
*s=*s+25;
if('a'<*s&&'z'>=*s)
*s=*s-1;
else if(*s=='a')
*s=*s+25;
}
}
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