task1_1.c
#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.c
#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;
}
task2_1.c
#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(s1, s2);
strcpy(s2, tmp);
printf("\nafter swap: \n");
printf("s1: %s\n", s1);
printf("s2: %s\n", s2);
return 0;
}
问题1：数组s1的大小是24；sizeof(s1)计算的是数组s1的大小，strlen(s1)统计的是除结束符外数组所占的空间。
问题2：不能，因为char s1[ ]定义时未标明字符串长度，违反语法规则。
问题3：line20-22执行后，字符数组s1和s2中的内容交换。
tas2_2.c
#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("\nswapping...\n");
tmp = s1;
s1 = s2;
s2 = tmp;
printf("\nafter swap: \n");
printf("s1: %s\n", s1);
printf("s2: %s\n", s2);
return 0;
}
问题1：
问题2：
问题3：
task3.c
#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++);
}
task4.c
#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.c
#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.c
#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+i]>0))
{
tmp = name[j];
name[j] = name[j+1];
name[j+1]=tmp;
}
}
task6_2.c
#include <stdio.h>
#include <stdlib.h>
void sort(char *name[],int n);
int main()
{
char *course[4]={"C Program",
"C++ Program",
"Operating System",
"Data Structure and Algorithms"};
int i;
sort(course,4);
for(i=0;i<4;i++)
printf("%s\n\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;
}
}
}
答：实现的是指针变量的值。
task7.c
#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])) // 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 flag=1;
char *p=str;
for(p=str;*p!='\0';p++)
{
flag=1;
if(str[17]!='X'&&(*p<48||*p>57))
flag=0;
}
if(flag==1&&strlen(str)==18)
return 1;
else
return 0;
}
task8.c
#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)
{
for(;*s!='\0';s++)
if(*s!='z'&&*s!='Z'&&(*s>=65&&*s<=90||*s>=97&&*s<=122))
*s+=1;
else if(*s=='z'||*s=='Z')
*s-=25;
}
void decoder(char *s)
{
for(;*s!='\0';s++)
if(*s!='a'&&*s!='A'&&(*s>=65&&*s<=90||*s>=97&&*s<=122))
*s-=1;
else if(*s=='a'||*s=='A')
*s+=25;
}
标签：int,s1,char,++,实验,str,printf From： https://www.cnblogs.com/15825859956jyx/p/17372013.html