day 6

1、指针封装strlen

  1 #include <stdio.h> 
  2 #include <string.h> 
  3 int main(int argc, const char *argv[]) 
  4 { 
  5     char arr[32]=" "; 
  6     gets(arr); 
  7     char *p=arr;
  8     int i=0,len;
  9     while(p[i]!='\0')
 10     {
 11         len++;
 12         i++;
 13     }
 14     printf("%d\n",len);
 15     return 0;
 16 }
                                     

2、指针封装strcat

  1 #include <stdio.h>
  2 #include <string.h>
  3 int main(int argc, const char *argv[])
  4 {
  5     char arr[30]=" ";
  6     char brr[30]=" ";
  7     gets(arr);
  8     gets(brr);
  9     char *pa=arr;
 10     char *pb=brr;
 11     int i=0,j=0;
 12     while(*pa!='\0')
 13     {
 14         pa++;
 15     }
 16     while(*pb!='\0')
 17     {
 18         *pa=*pb;
 19         pa++;
 20         pb++;
 21     }
 22     *pb='\0';
 23     puts(arr);
 24     puts(brr);
 25     return 0;
 26 }                                   

3、指针封装strcpy

  1 #include <stdio.h> 
  2 #include <string.h> 
  3 int main(int argc, const char *argv[]) 
  4 { 
  5     char arr[5]; 
  6     char brr[30]; 
  7     gets(arr); 
  8     gets(brr); 
  9     char *pa=arr; 
 10     char *pb=brr; 
 11     while(*pb!='\0') 
 12     { 
 13         *pa=*pb; 
 14         pa++; 
 15         pb++; 
 16     } 
 17     puts(arr); 
 18     return 0; 
 19 }

4、指针封装strcmp

  1 #include <stdio.h>
  2 #include <string.h>
  3 int main(int argc, const char *argv[])
  4 {
  5     char arr[30];
  6     char brr[30];
  7     gets(arr);
  8     int num=0;
  9     gets(brr);
 10     char *pa=arr;
 11     char *pb=brr;
 12     int flag=0;
 13     while(*pa!='\0'&&*pa==*pb&&*pb!='\0')
 14     {
 15         pa++;
 16         pb++;
 17     }
 18     num=*pa-*pb;
 19     if(num==0)
 20     {
 21         printf("num=%d pa==pb\n",num);
 22     }
 23     if(num>0)
 24     {
 25         printf("num=%d pa>pb\n",num);
 26     }
 27     if(num<0)
 28     {
 29         printf("num=%d pa<pb\n",num);
 30     }
 31     
 32     return 0;
 33 }