实验六

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>
#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;
    
}

2004;2001;数据类型不同

task2_1.c

#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;
}

task2_2.c

#include<stdio.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;
}

2004,2016;2001,2004;数据类型不同,且++q表示到下一行,增加了四个数的地址值。

task3_1.c

#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;
    
}

12;sizeof(s1)计算的是字节数,包括了结束符;strlen(s1)计算实际长度,不包括结束符;

不能;是

task3_2.c

#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;
    
    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;
}

s1字符串的地址;sizeof(s1)计算的是指针变量所占字节数;strlen(s1)统计的是实际长度;

交换的是地址;没有

task4.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]))
            printf("%s\tTrue\n",pid[i]);
        else
            printf("%s\tFalse\n",pid[i]);
    }
    
    return 0;
}

int check_id(char *str)
{
    int i;
        if(strlen(str)!=18)
            return 0;
    
    for(i=0;i<18;i++)
    {
        if(str[i]=='X'||(str[i]<='9'&&str[i]>='0'))
            continue;
        else
            return 0;
    }
    return 1;
}

 

task5.c

#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;
        long n,m;
        n=strlen(s);
        m=n/2;
        for(i=0;i<m-1;i++)
            if(s[i]!=s[n-i-1])
                return 0;
        return 1;
    }

 

task6.c

#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;i<N;i++)
    {
        if(*(s+i)=='z'||*(s+i)=='Z')
            *(s+i)-=25;
        else if((*(s+i)>='a'&&*(s+i)<'z')||(*(s+i)>='A'&&*(s+i)<'Z'))
            *(s+i)+=1;
    }
}

void decoder(char *s)
{
    int i;
    for(i=0;i<N;i++)
    {
        if(*(s+i)=='a'||*(s+i)=='A')
            *(s+i)+=25;
        else if((*(s+i)>'a'&&*(s+i)<='z')||(*(s+i)>'A'&&*(s+i)<='Z'))
            *(s+i)-=1;
    }
}

 

posted @ 2022-06-07 19:56  xryyyy  阅读(12)  评论(3编辑  收藏  举报