求公用字串的經典源碼

原始碼如下：

 

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

char *maxsubstr(char shortstring[], char longstring[])
{
  int i;
  int j;
  char *substr = malloc(256);
  longstring[strlen(longstring) - 1] = 'M';
  if(strstr(longstring, shortstring) != NULL)
    return shortstring;
  for(i = strlen(shortstring) - 1; i > 0; i--)
    for(j = 0; j < strlen(shortstring) - i; j++)
    {
      memcpy(substr, &shortstring[j], i);
      substr[i] = '/0';
      if(strstr(longstring, substr) != NULL)
        return substr;
    }
  return NULL;
}

 

int main(int argc, char **argv)
{
  char *str1 = malloc(256);
  char *str2 = malloc(256);
  char *common = NULL;
  puts("please input two strings:");
  scanf("%s %s", str1, str2);
  if(strlen(str1) < strlen(str2))
    common = maxsubstr(str1, str2);
  else
    common = maxsubstr(str2, str1);
  printf("the max common string is: %s/n", common);
  printf("/n%s", str2);
  return 0;
}