C语言字符串Trim()函数的实现

#include <stdio.h>
#include <string.h>
//trim:remove trailing blacks, tabs, newlines
int trim(char s[]);
int Trim(char s[]);
int main()
{
   char a[] = "hello world! ";
   int leng = trim(a);
   printf("The length is %d, %s@@\n",leng, a);
   printf("There are \"%d\" real characters left\n",Trim(a));
   printf("%s",a);
}
/*不使用库函数*/
int trim(char s[])
{
   /*函数中用到的变量，必须在一开始一次性全部声明*/
   int n = 0;
   int i;
   while(s[n++]!='\0')
   ;
   /*   while(s[n++]!='\0')
        ;
		等价于 while(s[n]!='\0')
		       n++;
  */
   for(i=n-2;i>=0;i--)
   {
      if((s[i]==' ')||(s[i]=='\t')||(s[i]=='\n'))
	  s[i] = '\0';
	  else
	  break;
   }
   return i;
}
/*使用string.h中的库函数*/
int Trim(char s[])
{
   int n;
   for(n = strlen(s) - 1; n >= 0; n--)
   {
      if(s[n]!=' ' && s[n]!='\t' && s[n]!='\n')
	  break;
	  s[n+1] = '\0';
   }
   return n;
}