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>

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

#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(tmp,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;
    char *s2;
    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;
}

task3

#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 *s

#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;
}

task4

#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';
}

 

tr1,char *str2)
{
    while(*str1)
      str1++;
      
      while(*str1++=str2++)
      ;
}

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

#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+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]={"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[j];
            name[i]=name[k];
            name[k]=tmp;
            
        }
       }
       
}