8.2 list pointer Array

The second-level pointer identifies the largest character:

 
 

  
  
#include <stdio.h>
  
  
char maxchar(char * str, char** max)
  
  
{
  
  
Char da = * STR; // first run the maximum first character
  
  
 *max = str;
  
  
 while (*str)
  
  
 {
  
  
 if (*str > da)
  
  
 {
  
  
 da = *str;
  
  
 *max = str;
  
  
 }
  
  
 str++;
  
  
 }
  
  
 return da;
  
  
}
  
  
int main()
  
  
{
  
  
 char str[] = "hello liuwxeia";
  
  
 char * max = NULL;
  
  
 char ch = maxchar(str, &max);
  
  
 printf("%p\t%c\n", max, ch);
  
  
 printf("%p\n", &str);
  
  
 return 0;
  
  
}
 
 

Pointer array: each element in the array is a pointer.
Int * A [5]; // A is an array. The five elements are pointer to int * D // sizeof (a) -----------> 20 bytes. Because a is an array, not a pointer // a pointer contains 4 bytes
Sort string Arrays:

 
 

  
  
#include <stdio.h>
  
  
void show_str(char **s, int n)
  
  
{
  
  
 int i;
  
  
 for (i = 0; i < n; i++)
  
  
 {
  
  
 printf("%s\n", s[i]);
  
  
 }
  
  
}
  
  
void sort_str(char **s, int n)
  
  
{
  
  
 int i, j, min;
  
  
 char * temp;
  
  
 for (i = 0; i < n; i++)
  
  
 {
  
  
 min = i;
  
  
 for (j = i + 1; j<n; j++)
  
  
 if (strcmp(s[min], s[j]) > 0)
  
  
 min = j;
  
  
 temp = s[min];
  
  
 s[min] = s[i];
  
  
 s[i] = temp;
  
  
 }
  
  
}
  
  
int main()
  
  
{
  
  
 char *s[] = { "hello", "world", "liuwei", "xuanyuan", "nima" };
  
  
 show_str(s, 5);
  
  
 sort_str(s, 5);
  
  
 printf("*****************\n");
  
  
 show_str(s, 5);
  
  
 return 0;
  
  
}
 
 

PS: the second-level pointer in the parameter is equivalent to the pointer array.
Two-dimensional arrays are equivalent to array pointers.


From Weizhi note (wiz)

8.2 list pointer Array